Water soluble fibers with post process modifications and articles containing same

ABSTRACT

Methods of treating fibers comprising a polymer including at least one of a vinyl acetate moiety or a vinyl alcohol moiety, and resulting fibers or the products comprising the resulting fibers are disclosed. In an example embodiment, a method of treating fibers includes contacting a surface of a fiber comprising the polymer with a modification agent to chemically modify at least a portion of the polymer with the modification agent in a region of the fiber comprising at least the surface of the fiber to form a modified fiber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/074,716, filed Sep. 4, 2020, which application is expresslyincorporated by reference herein in its entirety.

FIELD

The present disclosure relates generally to water soluble fibers. Moreparticularly, the disclosure relates to water soluble fibers comprisinga modified polymer comprising vinyl acetate moieties and/or vinylalcohol moieties after fiber formation by chemically modifying the vinylalcohol moieties in the polymer.

BACKGROUND

Nonwoven webs are traditionally used in many single-use consumerproducts including personal care products, such as bandages, diapercomponents, feminine care, and adult incontinence, and single-use wipes,such as in industrial applications, medical applications, cleaningapplications, and personal/baby care. Traditional chemistries used insuch products, e.g., viscose, polypropylene, or cotton fibers, aregenerally non-sustainable, non-biodegradable, are potential contributorsto microplastics, and are often disposed of incorrectly, such as byflushing down a toilet and entering wastewater treatment and sewagefacilities. Known wipes must be disposed of in a bin, which may not behygienic or convenient for a user. Improper disposal of these articlescan result in pipe clogs in the home, formation of “fatbergs” oraggregation of congealed mass of biodegradable and non-biodegradablematerials composed of congealed grease and cooking fat and disposablewipes in residential and municipal wastewater systems, contributing tooceanic microplastics, and require a change in consumer behavior.

The solubility profile and mechanism (e.g., hot-water soluble vs.cold-water soluble, readily soluble vs. delayed solubility or extendedrelease) of a water-soluble article may need to be adjusted based on theend use of the article. For articles including water-soluble fibers, thesolubility profile and mechanism can be varied by selecting fiberforming materials having different chemical modifications, such as,copolymerization. However, chemical modifications of fiber formingmaterials also influence the ability of the fiber forming material toform fibers. Thus, a fiber formed of a particular polymer having adesired chemical modification to provide a fiber having a desiredsolubility profile may not be accessible as the fiber forming materialmay not survive the fiber making process. Accordingly, it would beadvantageous to provide a method for modifying the solubility profile ofa fiber after fiber formation, in order to access otherwise unavailablesolubility profiles.

Additionally, the solubility profile, bondability, and other properties,such as mechanical properties and chemical compatibility, of a fiber orwater-soluble article prepared therefrom can be designed for aparticular end use. Thus, it would be advantageous to provide a methodfor improving bondability, expanding chemical compatibility and/or otherproperties of a fiber after fiber formation and/or maintaining ormodifying the solubility profile of a nonwoven web prior to assembly ina composite in order to manage inventory. Expanded chemicalcompatibility is used for applications for packaging and delivery. Theability to post-process modify the chemical make-up of a fiber and,thus, the solubility profile of a fiber, would advantageously allowaccess to various fiber types starting from one or a handful of fibertypes. The post-manufacturing fiber modification provides manyadvantages such as processability, process changes, and/or flexibilityof composition.

BRIEF DESCRIPTION OF THE DRAWINGS

For further facilitating the understanding of the present disclosure,twenty-four (24) drawing figures are appended hereto.

FIGS. 1A-1D show a transverse cross-section of various fiber shapes,wherein a line indicates a diameter of the fiber, according to exampleembodiments;

FIG. 2A shows a transverse cross-section of a round fiber characterizedby a core-sheath structure, wherein the polymer of the sheath (shell)202 has chemical modification or a higher degree of modification thanthe polymer of the core 201, according to example embodiments;

FIG. 2B shows a transverse cross-section of a round fiber characterizedby an increasing gradient in the degree of modification of the polymerfrom an interior region 301 to a surface region 302, according toexample embodiments;

FIG. 2C shows a transverse cross-section of a round fiber characterizedby the polymer having the same or equal degree of modification acrossthe transverse cross-section, according to example embodiments;

FIG. 3 shows a transverse cross-section of a round fiber having a firstregion, e.g., core region, 401, a second region, e.g., a sheath (shell)region 402, and at least one third region, e.g., two intermediateregions 403 a and 403 b, disposed between the first region and thesecond region, the cross section of the fiber characterized by anincreasing gradient in the degree of modification of the polymer fromthe first region to the second region, according to example embodiments;

FIG. 4A is a micrograph image of a nonwoven web of the disclosure havinga softness rating of 1, according to example embodiments;

FIG. 4B is a micrograph image of a nonwoven web of the disclosure havinga softness rating of 5, according to example embodiments;

FIG. 5 is an illustration of a nonwoven web noting exterior surfaces ofthe web as 100 and 101, according to example embodiments;

FIG. 6 shows ATR-FTIR results of a through-air nonwoven web comprising aplurality of fibers (Fiber A) without and with chemical modificationwith glutaric anhydride in THF at 60° C. for 5 hours, according toexample embodiments;

FIG. 7 shows ATR-FTIR results of a through-air nonwoven web comprising aplurality of fibers (Fiber A) without and with chemical modificationwith maleic anhydride in THF at 60° C. for 5 hours, according to exampleembodiments;

FIG. 8 shows ATR-FTIR results of a through-air nonwoven web comprising aplurality of fibers (Fiber A) without and with chemical modificationwith phthalic anhydride in THF at 60° C. for 5 hour, according toexample embodiments;

FIG. 9 shows ATR-FTIR results of a plurality of fibers (Fiber E) withoutand with chemical modification with maleic anhydride in THF at 60° C.for 5 hours, according to example embodiments;

FIG. 10 shows rupture time (seconds) of through-air nonwoven webs havinga plurality of fibers (Fiber A) without and with chemical modificationwith an anhydride such as maleic anhydride, glutaric anhydride, orphthalic anhydride, in THF at 60° C. for 5 hours, according to exampleembodiments;

FIG. 11 shows rupture time (seconds) of nonwoven webs having a pluralityof fibers (Fiber A) without and with chemical modification with maleicanhydride in DCM at room temperature for 5 hours, according to exampleembodiments;

FIG. 12 shows tensile strength of through-air nonwoven webs having aplurality of fibers (Fiber A) without and with chemical modificationwith an anhydride such as maleic anhydride, glutaric anhydride, orphthalic anhydride, in THF at 60° C. for 5 hours, according to exampleembodiments;

FIG. 13 shows tensile strength of nonwoven webs having a plurality offibers (Fiber A) without and with chemical modification with maleicanhydride in DCM at room temperature for 5 hours, according to exampleembodiments;

FIG. 14 shows a glycerin holding capacity (in percentage of retention)of through-air nonwoven webs having a plurality of fibers (Fiber A)without and with chemical modification with an anhydride, such as maleicanhydride, glutaric anhydride, or phthalic anhydride, in THF at 60° C.for 5 hours, wherein an initial loading of glycerin was 50%, accordingto example embodiments;

FIG. 15 shows a glycerin holding capacity (in percentage of retention)of nonwoven webs having a plurality of fibers (Fiber A) without and withchemical modification with maleic anhydride in in DCM at roomtemperature for 5 hours, wherein an initial loading of glycerin was 50%,according to example embodiments;

FIG. 16 shows a glycerin holding capacity (in percentage of retention)of through-air nonwoven webs having a plurality of fibers (Fiber A)without and with chemical modification with an anhydride, such as maleicanhydride, glutaric anhydride, or phthalic anhydride, in THF at 60° C.for 5 hours, wherein an initial loading of glycerin was 180%, accordingto example embodiments;

FIG. 17 shows a glycerin holding capacity (in percentage of retention)of nonwoven webs having a plurality of fibers (Fiber A) without and withchemical modification with maleic anhydride in in DCM at roomtemperature for 5 hours, wherein an initial loading of glycerin was180%, according to example embodiments; and

FIG. 18 shows ATR-FTIR results of an interior region (“inside region”)and a surface region (“outside region”) of an exemplary block comprisinga copolymer of vinyl acetate and vinyl alcohol without and with chemicalmodification with maleic anhydride in in THF at 60° C. for 5 hours,according to example embodiments.

DETAILED DESCRIPTION

Provided herein are methods of treating fibers to chemically modify apolymer that makes up the fiber, by contacting the fiber or a surfacethereof with a modification agent to chemically modify at least aportion of the polymer with the modification agent in a region of thefiber or a surface thereof and form a modified fiber. Also providedherein are method of treating fibers by admixing a fiber comprising apolymer, a modification agent, and optionally a solvent for themodification agent, to chemically modify at least a portion of thepolymer with the modification agent and form a modified fiber. Inembodiments, the fiber is not soluble in the solvent for a duration ofcontact of the fiber with the solvent. The methods of the disclosure canadvantageously provide a fiber having chemical modification or anincrease in the chemical modification of a polymer that makes up thefiber, a fiber having a core-sheath structure wherein the polymer of thesheath or surface region has a different amount of chemical modification(degree of modification) than the polymer of the core or interiorregion, and/or a fiber having a gradient of the chemical modification ofthe polymer that makes up the fiber, from an interior region to asurface region. Optionally, the polymer comprises at least one of avinyl acetate moiety or a vinyl alcohol moiety. As used herein, “atleast one of a vinyl acetate moiety or a vinyl alcohol moiety” and “avinyl acetate moiety and/or a vinyl alcohol moiety” describe anexemplary polymer comprising only a vinyl acetate moiety, only a vinylalcohol moiety, or both a vinyl acetate moiety and a vinyl alcoholmoiety. In the present disclosure, the singular forms “a,” “an,” and“the” include the plural reference, unless the context clearly indicatesotherwise. Thus, for example, a reference to “a vinyl alcohol moiety” isa reference to one or more of such structures and equivalents includingvinyl alcohol moieties. For example, such a polymer may be a copolymercomprising both a vinyl acetate moiety and a vinyl alcohol moiety, i.e.,a copolymer of vinyl acetate and vinyl alcohol.

One aspect of the disclosure provides a method of treating fibers tochemically modify a polymer that makes up the fiber, by contacting thefiber or a surface thereof with a modification agent to chemicallymodify at least a portion of the polymer with the modification agent ina region of the fiber or a surface thereof and form a modified fiber. Inembodiments, contacting the fiber or a surface thereof with amodification agent includes admixing a fiber comprising a polymercomprising vinyl acetate moieties and/or vinyl alcohol moieties, amodification agent, and optionally a solvent for the modification agent.

Another aspect of the disclosure provides a modified fiber, which ischemically modified with the modification agent, according to themethods of the disclosure.

Another aspect of the disclosure provides a fiber having a surfaceregion and an interior region. The fiber includes a modified polymercomprising vinyl acetate moieties and/or vinyl alcohol moieties. Thefiber has a transverse cross-section including the interior regioncomprising the polymer having a first degree of modification, and thesurface region comprising the polymer having a second degree ofmodification greater than the first degree of modification.

Another aspect of the disclosure provides a fiber comprising atransverse cross-section having a core-sheath structure. The fiberincludes a first region, e.g., a core region, comprising the polymerhaving a first degree of modification, and a second region, e.g., asheath region, comprising the polymer having a second degree ofmodification. The second degree of modification is different from, e.g.,greater than, the first degree of modification.

Another aspect of the disclosure provides a method of treating anonwoven web comprising a plurality of fibers. In example embodiments,each fiber of the plurality of fibers includes a polymer comprisingvinyl acetate moieties and/or vinyl alcohol moieties. The methodincludes contacting at least a portion of the nonwoven web with amodification agent to chemically modify the polymer in a region of eachfiber therein with the modification agent so as to provide a modifiednonwoven web.

Another aspect of the disclosure provides a modified nonwoven web, inwhich the polymer therein is chemically modified with the modificationagent according to the methods of the disclosure.

Another aspect of the disclosure provides a nonwoven web comprising amodified fiber of the disclosure.

Another aspect of the disclosure provides a multilayer nonwoven webcomprising a first layer comprising a nonwoven web treated according tothe methods of the disclosure or a nonwoven web comprising a fiber ofthe disclosure.

Another aspect of the disclosure provides a pouch comprising a nonwovenweb according to the disclosure in the form of a pouch defining aninterior pouch volume.

Another aspect of the disclosure provides a sealed article comprising anonwoven web of the disclosure.

Another aspect of the disclosure provides a flushable article comprisinga nonwoven web of the disclosure.

Another aspect of the disclosure provides a wearable absorbent article,the article comprising an absorbent core having a wearer facing side andan outer facing side and a liquid acquisition layer, wherein the liquidacquisition layer comprises a nonwoven web of the disclosure.

Further aspects and advantages will be apparent to those of ordinaryskill in the art from a review of the following detailed description.While the fibers, nonwoven webs, pouches, articles and their methods ofmaking are susceptible of embodiments in various forms, the descriptionhereafter includes specific embodiments with the understanding that thedisclosure is illustrative and is not intended to limit the invention tothe specific embodiments described herein.

In embodiments, the fibers of the disclosure are water-soluble prior totreatment with the modification agent and remain water-soluble aftertreatment with the modification agent. In embodiments, the fibers of thedisclosure are cold-water soluble prior to treatment with themodification agent and are hot-water soluble after treatment with themodification agent. In embodiments, the fibers of the disclosure arecold-water soluble prior to treatment with the modification agent and atleast a portion of the exterior surface of the fiber is hot-watersoluble after treatment with the modification agent. In embodiments, thefibers of the disclosure are hot-water soluble prior to treatment withthe modification agent and are cold-water soluble after treatment withthe modification agent. In embodiments, the fibers of the disclosure arehot-water soluble prior to treatment with the modification agent and atleast a portion of the exterior surface of the fiber is cold-watersoluble after treatment with the modification agent. In embodiments, thefibers of the disclosure are cold-water soluble prior to treatment withthe modification agent and remain cold-water soluble after treatmentwith the modification agent. In embodiments, the fiber is notwater-soluble prior to treatment with the modification agent and thefiber is water-soluble after treatment with the modification agent. Inembodiments, the fiber is not water-soluble after admixing the fiberwith the modification agent.

The methods and fibers of the disclosure can provide one or moreadvantages, including but not limited to, providing control over themicrostructure of the a fiber, modifying the solubility profile and/ormechanism of a fiber, enhancing the chemical compatibility of a fiber toa chemical agent, increasing the absorbance capacity of a fiber,increasing and/or controlling the loading of an active agent to theinterior of a fiber, providing control over the release of a compositionor active from the interior of a fiber, increasing inter-fiber cohesionvia intermolecular forces and creating crosslinking sites via covalentbond formation, improving processability of the fibers and nonwoven websformed therefrom (e.g., allowing nonwoven bonding using thru-airbonding, improving tensile strength, providing anchoring points foradditional functionality, and allowing triggered delivery of activeagents).

Unless expressly indicated otherwise, the term “degree of hydrolysis” isunderstood as a percentage (e.g., a molar percentage) of hydrolyzedmoieties among all hydrolyzable moieties a polymer initially has. Forexample, for a polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety, partial replacement of an ester group invinyl acetate moieties with a hydroxyl group occurs during hydrolysis,and a vinyl acetate moiety becomes a vinyl alcohol moiety. The degree ofhydrolysis of a polyvinyl acetate homopolymer is considered as zero,while the degree of hydrolysis of a polyvinyl alcohol homopolymer is100%. The degree of hydrolysis of a copolymer of vinyl acetate and vinylalcohol is equal to a percentage of vinyl alcohol moieties among a totalof vinyl acetate and vinyl alcohol moieties, and is between zero and100%.

As used herein and unless specified otherwise, the term “degree ofmodification” as it relates to chemical modification as describedherein, refers to the amount of chemical modification provided to apolymer backbone of a fiber described herein. For example, a polyvinylalcohol copolymer backbone can include vinyl alcohol monomer units(moieties) and vinyl acetate monomer units (moieties), depending on thedegree of hydrolysis, and if a polyvinyl alcohol has been modified by 2mol % with monomethyl maleate, based on the total amount of vinylalcohol monomer units and vinyl acetate monomer units, the degree ofmodification of the polyvinyl alcohol is 2 mol %. As used herein andunless specified otherwise, a copolymer having two or more monomer unitsin the backbone is not considered a modified polymer, unless thebackbone units have been chemically modified after fiber formation, asdescribed herein. For example, a polyvinyl alcohol copolymer comprisingvinyl alcohol monomer units, vinyl acetate monomer units, and monomethylmaleate monomer units, wherein the monomethyl maleate monomer units makeup 2 mol % of the total backbone monomer units is not considered to havea degree of modification of 2 mol %. However, such a copolymer can bechemically modified by, e.g., 3 mol % monomethyl maleate, to provide acopolymer comprising 2 mol % monomethyl maleate backbone units with a 3mol % monomethyl maleate modification. As used herein and unlessspecified otherwise, the terms “chemical modification” and “chemicallymodify” refer to a modification of a polymer backbone of a fiber,wherein the chemical modification does not include hydrolyzing thepolymer and wherein the chemical modification does not increase theamount of backbone monomer units. For example, a polyvinyl alcoholcopolymer backbone can include vinyl alcohol monomer units and vinylacetate monomer units, depending on the degree of hydrolysis, and if thepolyvinyl alcohol is said to be chemically modified herein, the totalamount of vinyl alcohol monomer units and vinyl acetate monomer unitsdecreases by the amount of chemical modification (degree ofmodification), relative to the unmodified or non-modified polymer, asthe vinyl alcohol monomer units and/or vinyl acetate monomer units havebeen transformed into a modified monomer unit. It is possible for apolymer of a fiber disclosed herein to have a degree of modificationprior to further chemically modifying the polymer of the fiber, and assuch, the total degree of modification would include the degree ofmodification prior to further chemically modifying the polymer of thefiber, added to the degree of modification that occurred from themodification agent disclosed herein. In some embodiments, the hydroxyl(—OH) groups in the vinyl alcohol moieties react with the modificationagent and the polymer backbone is chemically boned with the moieties ofthe modification agent.

As used herein and unless specified otherwise, the term “water-soluble”refers to any nonwoven web or article containing same having adissolution time of 300 seconds or less at a specified temperature asdetermined according to a method for testing dissolution time anddisintegration time (MSTM-205) as set forth herein, or any fiber havingcomplete dissolution time of less than 30 seconds at a specifiedtemperature according to the method for determining single fibersolubility disclosed herein. For example, the solubility parameters canbe characteristic of a nonwoven web having a thickness of 6 mil (about152 μm), or an article made therefrom. The dissolution time of thenonwoven web optionally can be 200 seconds or less, 100 seconds or less,60 seconds or less, or 30 seconds or less at a temperature of about 100°C., about 90° C., about 80° C., about 70° C., about 60° C., about 50°C., about 40° C., about 20° C., or about 10° C. In embodiments whereinthe dissolution temperature is not specified, the water-soluble nonwovenweb has a dissolution time of 300 seconds or less at a temperature nogreater than about 100° C. A fiber can have a complete dissolution timeof 30 seconds or less at a temperature of about 100° C., about 90° C.,about 80° C., about 70° C., about 60° C., about 50° C., about 40° C.,about 20° C., or about 10° C. As used herein, a fiber is “insoluble,”“water-insoluble,” “non-water-soluble” or “insoluble in water” when thefiber has a complete dissolution time of greater than 30 seconds at aspecified temperature according to the method for determining singlefiber solubility disclosed herein. In embodiments wherein the completedissolution temperature is not specified, a water-soluble fiber has acomplete dissolution time of 30 seconds or less at a temperature nogreater than about 100° C. and a water-insoluble fiber has a completedissolution time of greater than 30 seconds at a temperature no greaterthan about 100° C. As used herein and unless specified otherwise, theterm “cold water-soluble” refers to any nonwoven web having adissolution time of 300 seconds or less at 10° C. as determinedaccording to MSTM-205. For example, the dissolution time optionally canbe 200 seconds or less, 100 seconds or less, 60 seconds or less, or 30seconds at 10° C. As used herein and unless specified otherwise, theterm “cold water-soluble” in connection with a fiber refers to a fiberhaving a complete dissolution time of 30 seconds or less at atemperature of 10° C. or less, according to the method for determiningsingle fiber solubility disclosed herein.

As used herein and unless specified otherwise, the term“water-dispersible” refers to a nonwoven web, or article containing samewherein upon submersion in water at a specified temperature the nonwovenweb or article physically disassociates into smaller constituent pieces.The smaller pieces may or may not be visible to the naked eye, may ormay not remain suspended in the water, and may or may not ultimatelydissolve. In embodiments wherein a dispersion temperature is notspecified, the nonwoven web or pouch will disintegrate in 300 seconds orless at a temperature of about 100° C. or less, according to MSTM-205.For example, the disintegration time optionally can be 200 seconds orless, 100 seconds or less, 60 seconds or less, or 30 seconds or less ata temperature of about 80° C., about 70° C., about 60° C., about 50° C.,about 40° C., about 20° C., or about 10° C., according to MSTM-205. Forexample, such dispersion parameters can be characteristic of a nonwovenweb having a thickness of 6 mil (about 152 μm), or an article madetherefrom.

As used herein, the term “flushable” refers to an article such as anonwoven web, or pouch that is dispersible in aqueous environments, forexample, a liquid sewage system, such that the disposal of the web(s) orpouch(es) does not result in the catching of such articles within thepipes of a plumbing system or building up over time to cause a blockageof such a pipe. The INDA/EDANA standard for flushability requires thatgreater than 95% of the starting material must pass through a 12.5 mmsieve after 60 minutes of slosh box testing using 28 RPM (revolutionsper minute) and 18° tilt angle. The Flushability Test set forth hereinprovides a more stringent flushability test. A commercially availablenonwoven web in the form of a flushable wipe, herein referred to asCommercial Wipe A, is certified as flushable and has a disintegrationtime of 20 seconds as measured by the Flushability Test set forthherein. Thus, as used herein and unless specified otherwise, the term“flushable” refers to an article such as a nonwoven web or pouch thathas a percent disintegration that meets or exceeds the percentdegradation of Commercial Wipe A (20%) as measured by the FlushabilityTest as set forth herein. Flushable nonwoven webs and articlescontaining same have the advantage of being more processable inrecycling processes or can simply be flushed in, for example, septic andmunicipal sewage treatment systems such that, after use, the web,structure, or pouch does not need to be landfilled, incinerated, orotherwise disposed of.

As used herein and unless specified otherwise, the term “nonwoven web”refers to a web or sheet comprising, consisting of, or consistingessentially of fibers arranged (e.g., by a carding process) and bondedto each other. Thus, the term nonwoven web can be considered short handfor nonwoven fiber-based webs. Further, as used herein, “nonwoven web”includes any structure including a nonwoven web or sheet, including, forexample, a nonwoven web or sheet having a film laminated to a surfacethereof. Methods of preparing nonwoven webs from fibers are well knownin the art, for example, as described in Nonwoven Fabrics Handbook,prepared by Ian Butler, edited by Subhash Batra et al., Printing byDesign, 1999, herein incorporated by reference in its entirety. As usedherein and unless specified otherwise, the term “film” refers to acontinuous film or sheet, e.g., prepared by a casting or extrusionprocess.

“Comprising” as used herein means that various components, ingredientsor steps that can be conjointly employed in practicing the presentdisclosure. Accordingly, the term “comprising” encompasses the morerestrictive terms “consisting essentially of” and “consisting of.” Thepresent compositions can comprise, consist essentially of, or consist ofany of the required and optional elements disclosed herein. For example,a thermoformed packet can “consist essentially of” a nonwoven webdescribed herein for use of its thermoforming characteristics, whileincluding a non-thermoformed film or nonwoven web (e.g., lid portion),and optional markings on the film, e.g., by inkjet printing. Thedisclosure illustratively disclosed herein suitably may be practiced inthe absence of any element or step, which is not specifically disclosedherein.

All percentages, parts and ratios referred to herein are based upon thetotal dry weight of the nonwoven web or film composition or total weightof the packet content composition of the present disclosure, as the casemay be, and all measurements made are at about 25° C., unless otherwisespecified. All such weights as they pertain to listed ingredients arebased on the active level and therefore do not include carriers orby-products that may be included in commercially available materials,unless otherwise specified.

All ranges set forth herein include all possible subsets of ranges andany combinations of such subset ranges. By default, ranges are inclusiveof the stated endpoints, unless stated otherwise. Where a range ofvalues is provided, it is understood that each intervening value betweenthe upper and lower limit of that range and any other stated orintervening value in that stated range, is encompassed within thedisclosure. The upper and lower limits of these smaller ranges mayindependently be included in the smaller ranges, and are alsoencompassed within the disclosure, subject to any specifically excludedlimit in the stated range. Where the stated range includes one or bothof the limits, ranges excluding either or both of those included limitsare also contemplated to be part of the disclosure.

It is expressly contemplated that for any number value described herein,e.g., as a parameter of the subject matter described or part of a rangeassociated with the subject matter described, an alternative which formspart of the description is a functionally equivalent range surroundingthe specific numerical value (e.g., for a dimension disclosed as “40 mm”an alternative embodiment contemplated is “about 40 mm”).

As used herein, the terms packet(s) and pouch(es) should be consideredinterchangeable. In certain embodiments, the terms packet(s) andpouch(es), respectively, are used to refer to a container made using thenonwoven web and/or film, and to a fully-sealed container preferablyhaving a material sealed therein, e.g., in the form a measured dosedelivery system. The sealed pouches can be made from any suitablemethod, including such processes and features such as heat sealing,solvent welding, and adhesive sealing (e.g., with use of a water-solubleadhesive).

As used herein and unless specified otherwise, the terms “wt. %” and “wt%” are intended to refer to the composition of the identified element in“dry” (non-water) parts by weight of the entire article or compositionreferred to, for example a nonwoven web or film, including residualmoisture in the nonwoven web or film (when applicable), or laminatestructure, or parts by weight of a composition enclosed within a pouch(when applicable).

As used herein and unless specified otherwise, the term “PHR” (“phr”) isintended to refer to the composition of the identified element in partsper one hundred parts water-soluble polymer (whether PVOH or otherpolymers, unless specified otherwise) in the polymer-containing articlereferred to, e.g., a water-soluble film, a fiber, or a nonwoven web, ora solution used to make the fiber or film.

The nonwoven webs, pouches, and related articles and methods of makingand use are contemplated to include embodiments including anycombination of one or more of the additional optional elements,features, and steps further described below (including those shown inthe Examples and figures), unless stated otherwise.

Fiber Forming Materials

In general, the fibers of the disclosure can include a single fiberforming material or a combination (i.e., blend) of fiber formingmaterials. A single fiber can include one of more water-soluble fiberforming materials, one or more non-water-soluble fiber formingmaterials, or a combination of water-soluble and non-water-soluble fiberforming materials. The fibers of the disclosure can generally include asynthetic fiber forming material, a natural fiber forming material, aplant based fiber forming material, a bio-based fiber forming material,a biodegradable fiber forming material, a compostable fiber formingmaterial, or a combination thereof. Plant-based fiber forming materialscan be naturally occurring (e.g., cotton) or re-constituted (e.g.,bamboo).

In general, the fibers of the disclosure include a fiber formingmaterial that, prior to contact with a modification agent, includes afunctional group that can be chemically modified. As used herein,functional groups that can be chemically modified generally include, butare not limited to, any functional group that can undergo anesterification, amidation, amination, carboxylation, nitration, acyloincondensation, allylation, acetylaction, imidization, halogenation,sulfonation, alkylation, acetalyzation, enolyzation, nitrosation, andsilane coupling. Suitable polymers including a functional group that canbe chemically modified include polyvinyl acetate, polyvinyl propionate,polyvinyl alcohol polymers, poly(N-vinylacetamide) polymers, polyvinylbutyral polymers, poly(butyl acrylate) polymers, poly(butylmethacrylate) polymers, cellulose acetate polymers, polyacrylonitrilepolymers, poly(N-isopropylacrylamide) polymers,poly(N,N-diethylacrylamide) polymers, poly(N,N-dimethylacrylamide)polymers, polyl(methylvinylether) polymers, poly(N,N-di methylaminoethylmethacrylate) polymers, poly(N-vinylformamide) polymers,poly(N-vinylcaprolactam) polymers, polyvinylpyrrolidone polymers,polylactic acid, and combinations thereof.

In embodiments, the fibers of the disclosure can include a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety. In some embodiments, suitable examples of a polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moietyinclude, without limitation, a polyvinyl alcohol homopolymer, apolyvinyl acetate homopolymer, a polyvinyl alcohol copolymer, a modifiedpolyvinyl alcohol copolymer, and combinations thereof. For example, thepolyvinyl alcohol copolymer is a copolymer of vinyl acetate and vinylalcohol in some embodiments. For example, in some embodiments, themodified polyvinyl alcohol copolymer comprises an anionically modifiedcopolymer, which may be a copolymer of vinyl acetate and vinyl alcoholfurther comprising additional groups such as a carboxylate, a sulfonate,or combinations thereof. Such a polymer comprising at least one of avinyl acetate moiety or a vinyl alcohol moiety may also include anadditional polymer, for example, in a blend. In some embodiments, thehydroxyl (—OH) groups in the vinyl alcohol moieties react with themodification agent for chemical modification of the polymer.

Polyvinyl alcohol is a synthetic polymer generally prepared by thealcoholysis, usually termed hydrolysis or saponification, of polyvinylacetate. Fully hydrolyzed PVOH, where virtually all the acetate groupshave been converted to alcohol groups, is a strongly hydrogen-bonded,highly crystalline polymer which dissolves only in hot water—greaterthan about 140° F. (about 60° C.). If a sufficient number of acetategroups are allowed to remain after the hydrolysis of polyvinyl acetate,that is the PVOH polymer is partially hydrolyzed, then the polymer ismore weakly hydrogen-bonded, less crystalline, and is generally solublein cold water—less than about 50° F. (about 10° C.). As such, thepartially hydrolyzed polymer is a vinyl alcohol-vinyl acetate copolymerthat is a PVOH (polyvinyl alcohol) copolymer, but is commonly referredto as “polyvinyl alcohol (PVOH)” or “the PVOH polymer.” For brevity, theterm “the PVOH polymer” as used herein is understood to encompass ahomopolymer, a copolymer, and a modified copolymer comprising vinylalcohol moieties, for example, 50% or higher of vinyl alcohol moieties.The term “the PVOH fiber” as used herein is understood to encompass afiber comprising a homopolymer, a copolymer, and a modified copolymercomprising vinyl alcohol moieties, for example, 50% or higher of vinylalcohol moieties; and a fiber comprising such a polymer chemicallymodified with a modification agent. The chemically modified fiber maycomprise no vinyl alcohol moieties or less than 50% of vinyl alcoholmoieties.

The fibers described herein can include polyvinyl acetate, one or morepolyvinyl alcohol (PVOH) homopolymers, one or more polyvinyl alcoholcopolymers, or a combination thereof. As used herein, the term“homopolymer” generally includes polymers having a single type ofmonomeric repeating unit (e.g., a polymeric chain consisting of orconsisting essentially of a single monomeric repeating unit). For theparticular case of PVOH, the term “the PVOH polymer”) as an example of apolymer for chemical modification includes copolymers consisting of adistribution of vinyl alcohol monomer units and vinyl acetate monomerunits, depending on the degree of hydrolysis (e.g., a polymeric chainconsisting of or consisting essentially of vinyl alcohol and vinylacetate monomer units). In the limiting case of 100% hydrolysis, a PVOHpolymer can include a true homopolymer having only vinyl alcohol units.In some embodiments, the fibers and/or films of the disclosure includepolyvinyl alcohol copolymers. In some embodiments, the fibers and/orfilms of the disclosure include hot water-soluble polyvinyl alcoholcopolymers.

In some embodiments, the polymer for chemical modification includes apolyvinyl alcohol copolymer or higher polymer (e.g., ter-polymer)including one or more monomers in addition to the vinyl acetate/vinylalcohol groups. Optionally, the additional monomer is neutral, e.g.,provided by an ethylene, propylene, N-vinylpyrrolidone or othernon-charged monomer species. Optionally, the additional monomer iscationic, e.g., provided by a positively charged monomer species.Optionally, the additional monomer is anionic. Thus, in someembodiments, the polyvinyl alcohol includes an anionic polyvinyl alcoholcopolymer. An anionic polyvinyl alcohol copolymer can include apartially or fully hydrolyzed PVOH copolymer that includes an anionicmonomer unit, a vinyl alcohol monomer unit, and optionally a vinylacetate monomer unit (i.e., when not completely hydrolyzed). In someembodiments, the PVOH copolymer can include two or more types of anionicmonomer units. General classes of anionic monomer units which can beused for the PVOH copolymer include the vinyl polymerization unitscorresponding to sulfonic acid vinyl monomers and their esters,monocarboxylic acid vinyl monomers, their esters and anhydrides,dicarboxylic monomers having a polymerizable double bond, their estersand anhydrides, and alkali metal salts of any of the foregoing. Examplesof suitable anionic monomer units include the vinyl polymerization unitscorresponding to vinyl anionic monomers including vinyl acetic acid,maleic acid, monoalkyl maleate, dialkyl maleate, maleic anhydride,fumaric acid, monoalkyl fumarate, dialkyl fumarate, itaconic acid,monoalkyl itaconate, dialkyl itaconate, citraconic acid, monoalkylcitraconate, dialkyl citraconate, citraconic anhydride, mesaconic acid,monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid, monoalkylglutaconate, dialkyl glutaconate, glutaconic anhydride, alkyl acrylates,alkyl alkacrylates, vinyl sulfonic acid, allyl sulfonic acid, ethylenesulfonic acid, 2-acrylamido-1-methyl propane sulfonic acid,2-acrylamide-2-methylpropanesulfonic acid,2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate,alkali metal salts of the foregoing (e.g., sodium, potassium, or otheralkali metal salts), esters of the foregoing (e.g., methyl, ethyl, orother C₁-C₄ or C₆ alkyl esters), and combinations of the foregoing(e.g., multiple types of anionic monomers or equivalent forms of thesame anionic monomer). In some embodiments, the PVOH copolymer caninclude two or more types of monomer units selected from neutral,anionic, and cationic monomer units.

The level of incorporation of the one or more monomer units in the PVOHcopolymers is not particularly limited. In embodiments, the one or moremonomer units are present in the PVOH copolymer in an amount in a rangeof about 1 mol. % or 2 mol. % to about 6 mol. % or 10 mol. % (e.g., atleast 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4.0 mol. % and/or up to about3.0, 4.0, 4.5, 5.0, 6.0, 8.0, or 10 mol. % in various embodiments). Inembodiments, the additional monomer units can be an anionic monomerunits and the anionic monomer units are present in the PVOH copolymer inan amount in a range of about 1 mol. % or 2 mol. % to about 6 mol. % or10 mol. % (e.g., at least 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4.0 mol. %and/or up to about 3.0, 4.0, 4.5, 5.0, 6.0, 8.0, or 10 mol. % in variousembodiments).

Polyvinyl alcohols can be subject to changes in solubilitycharacteristics. The acetate group in the copolymer of vinyl acetate andvinyl alcohol (PVOH copolymer) is known by those skilled in the art tobe hydrolysable by either acid or alkaline hydrolysis. As the degree ofhydrolysis increases, a polymer composition made from the PVOH copolymerwill have increased mechanical strength but reduced solubility at lowertemperatures (e.g., requiring hot water temperatures for dissolution).Accordingly, exposure of a PVOH copolymer to an alkaline environment(e.g., resulting from a laundry bleaching additive) can transform thepolymer from one which dissolves rapidly and entirely in a given aqueousenvironment (e.g., a cold water medium) to one which dissolves slowlyand/or incompletely in the aqueous environment, potentially resulting inundissolved polymeric residue at the end of a wash cycle.

PVOH copolymers with pendant carboxyl groups, such as, for example,vinyl alcohol/hydrolyzed methyl acrylate sodium salt polymers, can formlactone rings between neighboring pendant carboxyl and alcohol groups,thus reducing the water solubility of the PVOH copolymer. In thepresence of a strong base, the lactone rings can open over the course ofseveral weeks at relatively warm (ambient) and high humidity conditions(e.g., via lactone ring-opening reactions to form the correspondingpendant carboxyl and alcohol groups with increased water solubility).Thus, contrary to the effect observed with PVOH copolymers of vinylacetate and vinyl alcohol, it is believed that such a PVOH copolymerpendant carboxyl groups can become more soluble due to chemicalinteractions between the polymer and an alkaline composition inside apouch during storage.

Specific sulfonic acids and derivatives thereof having polymerizablevinyl bonds can be copolymerized with vinyl acetate to providecold-water-soluble PVOH polymers, which are stable in the presence ofstrong bases. The base-catalyzed alcoholysis products of thesecopolymers, which are used in the formulation of water-soluble film, arevinyl alcohol-sulfonate salt copolymers which are rapidly soluble. Thesulfonate group in the PVOH copolymer can revert to a sulfonic acidgroup in the presence of hydrogen ions, but the sulfonic acid groupstill provides excellent cold-water solubility to the polymer. Inembodiments, vinyl alcohol-sulfonate salt copolymers contain no residualacetate groups (i.e., are fully hydrolyzed) and therefore are notfurther hydrolysable by either acid or alkaline hydrolysis. Generally,as the amount of co-monomer increases, the water solubility increases,thus sufficient inclusion of sulfonate or sulfonic acid groups inhibithydrogen bonding and crystallinity, enabling solubility in cold water.In the presence of acidic or basic species, the copolymer is generallyunaffected, with the exception of the sulfonate or sulfonic acid groups,which maintain excellent cold water solubility even in the presence ofacidic or basic species. Examples of suitable sulfonic acid comonomers(and/or their alkali metal salt derivatives) include vinyl sulfonicacid, allyl sulfonic acid, ethylene sulfonic acid,2-acrylamido-1-methylpropanesulfonic acid,2-acrylamido-2-methylpropanesufonic acid, 2-methacrylamido-2-methylpropanesulfonic acid and 2-sulfoethyl acrylate, with the sodium salt of2-acrylamido-2-methylpropanesulfonic acid (AMPS) being a preferredcomonomer.

The fiber forming polymers, whether polyvinyl alcohol polymers orotherwise, can be blended. When the polymer blend includes a blend ofpolyvinyl alcohol polymers, the PVOH polymer blend can include a firstPVOH polymer (“first PVOH polymer”), which can include a PVOH copolymeror a modified PVOH copolymer including one or more types of anionicmonomer units (e.g., a PVOH ter- (or higher co-) polymer), and a secondPVOH polymer (“second PVOH polymer”), which can include a PVOH copolymeror a modified PVOH copolymer including one or more types of anionicmonomer units (e.g., a PVOH ter- (or higher co-) polymer). In someaspects, the PVOH polymer blend includes only the first PVOH polymer andthe second PVOH polymer (e.g., a binary blend of the two polymers).Alternatively or additionally, the PVOH polymer blend or a fiber ornonwoven web made therefrom can be characterized as being free orsubstantially free from other polymers (e.g., other polymers generally,other PVOH-based polymers specifically, or both). As used herein,“substantially free” means that the first and second PVOH polymers makeup at least 95 wt. %, at least 97 wt. %, or at least 99 wt. % of thetotal amount of water-soluble polymers in the water-soluble fiber orfilm. In other aspects, the fiber can include one or more additionalwater-soluble polymers. For example, the PVOH polymer blend can includea third PVOH polymer, a fourth PVOH polymer, a fifth PVOH polymer, etc.(e.g., one or more additional PVOH copolymers or modified PVOHcopolymers, with or without anionic monomer units). For example, thefiber can include at least a third (or fourth, fifth, etc.)water-soluble polymer which is other than a PVOH polymer (e.g., otherthan PVOH homopolymers or PVOH copolymers, with or without anionicmonomer units).

The degree of hydrolysis (DH) of the PVOH copolymers included in thefibers of the present disclosure before chemical modification with amodification agent can be in a range of about 75% to about 99.9% (e.g.,about 79% to about 99.9%, about 79% to about 92%, about 80% to about90%, about 88% to 92%, about 86.5% to about 89%, or about 88%, 90% or92% such as for cold-water-soluble compositions; about 90% to about 99%,about 92% to about 99%, about 95% to about 99%, about 98% to about 99%,about 98% to about 99.9%, about 96%, about 98%, about 99%, or greaterthan 99%). As the degree of hydrolysis is reduced, a fiber made from thepolymer will have reduced mechanical strength but faster solubility attemperatures below about 20° C. As the degree of hydrolysis increases, afiber or film made from the polymer will tend to be mechanicallystronger and the thermoformability will tend to decrease. The degree ofhydrolysis of the PVOH can be chosen such that the water-solubility ofthe polymer is temperature dependent, and thus the solubility of a fibermade from the polymer is also influenced. In one option the fiber iscold water-soluble. For a copolymer of vinyl acetate and vinyl alcoholthat does not include any other monomers (e.g., a copolymer notcopolymerized with an anionic monomer) a cold water-soluble fiber,soluble in water at a temperature of less than 10° C., can include PVOHwith a degree of hydrolysis in a range of about 75% to about 90%, or ina range of about 80% to about 90%, or in a range of about 85% to about90%. In another option the fiber is hot water-soluble. For a copolymerof vinyl acetate and vinyl alcohol that does not include any othermonomers (e.g., a copolymer not copolymerized with an anionic monomer) ahot water-soluble fiber, soluble in water at a temperature of at leastabout 60° C., can include PVOH with a degree of hydrolysis of at leastabout 98%. A copolymer of vinyl acetate and vinyl alcohol may bereferred to as a PVOH copolymer, while a copolymer of vinyl acetate andvinyl alcohol including an anionic monomer moiety may be referred to asmodified PVOH copolymer or anionically modified PVOH copolymer. Both aPVOH copolymer and a modified PVOH copolymer can be the polymer in afiber before chemical modification with a modification agent.

The degree of hydrolysis of the polymer blend can also be characterizedby the arithmetic weighted, average degree of hydrolysis (H°). Forexample, H° for a PVOH polymer that includes two or more PVOH polymersis calculated by the formula H°=Σ(Wi·H_(i)) where W_(i) is the weightpercentage of the respective PVOH polymer and H_(i) is the respectivedegrees of hydrolysis. When a polymer is referred to as having aspecific degree of hydrolysis, the polymer can be a single polyvinylalcohol polymer having the specified degree of hydrolysis or a blend ofpolyvinyl alcohol polymers having an average degree of hydrolysis asspecified.

The viscosity of a PVOH polymer (μ) is determined by measuring a freshlymade solution using a Brookfield LV type viscometer with UL adapter asdescribed in British Standard EN ISO 15023-2:2006 Annex E BrookfieldTest method. It is international practice to state the viscosity of 4%aqueous polyvinyl alcohol solutions at 20° C. All viscosities specifiedherein in Centipoise (cP) should be understood to refer to the viscosityof 4% aqueous polyvinyl alcohol solution at 20° C., unless specifiedotherwise. Similarly, when a polymer is described as having (or nothaving) a particular viscosity, unless specified otherwise, it isintended that the specified viscosity is the average viscosity for thepolymer, which inherently has a corresponding molecular weightdistribution, i.e., the weighted natural log average viscosity asdescribed below. It is well known in the art that the viscosity of PVOHpolymers is correlated with the weight average molecular weight (Mw) ofthe PVOH polymer, and often the viscosity is used as a proxy for the Mw.

In embodiments, the PVOH polymer can have a viscosity of about 1.0 toabout 50.0 cP, about 1.0 to about 40.0 cP, or about 1.0 to about 30.0cP, for example about 4 cP, 8 cP, 15 cP, 18 cP, 23 cP, or 26 cP. Inembodiments, the PVOH homopolymers and/or copolymers can have aviscosity of about 1.0 to about 40.0 cP, or about 5 cP to about 23 cP,for example, about 1 cP, 1.5 cP, 2 cP, 2.5 cP, 3 cP, 3.5 cP, 4 cP, 4.5cP, 5 cP, 5.5 cP, 6 cP, 6.5 cP, 7 cP, 7.5 cP, 8 cP, 8.5 cP, 9 cP, 9.5cP, 10 cP, 11 cP, 12 cP, 13 cP, 14 cP, 15 cP, 17.5 cP, 18 cP, 19 cP, 20cP, 21 cP, 22 cP, 23 cP, 24 cP, 25 cP, 26 cP, 27 cP, 28 cP, 29 cP, 30cP, 31 cP, 32 cP, 33 cP, 34 cP, 35 cP, or 40 cP. In embodiments, thePVOH homopolymers and/or copolymers can have a viscosity of about 21 cPto 26 cP. In embodiments, the PVOH homopolymers and/or copolymers canhave a viscosity of about 5 cP to about 14 cP. In embodiments, the PVOHhomopolymers and/or copolymers can have a viscosity of about 5 cP toabout 23 cP.

For reference, in a polymer blend, the first PVOH polymer is denoted ashaving a first 4% solution viscosity at 20° C. (μ₁), and the second PVOHpolymer is denoted as having a second 4% solution viscosity at 20° C.(μ₂). In various embodiments, the first viscosity p_(i) can be in arange of about 4 cP to about 70 cP (e.g., at least about 4, 8, 10, 12,or 16 cP and/or up to about 12, 16, 20, 24, 28, 30, 32, 35, 37, 40, 45,48, 50, 56, 60, or 70 cP, such as about 4 cP to about 70 cP, about 4 cPto about 60 cP, about 4 cP to about 46 cP, about 4 cP to about 24 cP,about 10 cP to about 16 cP, or about 10 cP to about 20 cP, or about 20cP to about 30 cP). Alternatively or additionally, the second viscosityp₂ can be in a range of about 4 cP to about 70 cP (e.g., at least about4, 8, 10, 12, or 16 cP and/or up to about 12, 16, 20, 24, 28, 30, 32,35, 37, 40, 45, 48, 50, 56, 60, or 70 cP, such as about 12 cP to about30 cP, about 10 cP to about 16 cP, or about 10 cP to about 20 cP, orabout 20 cP to about 30 cP). When the PVOH polymer blend includes threeor more PVOH polymers selected from PVOH polymer and PVOH copolymers,the foregoing viscosity values can apply to each PVOH polymer or PVOHcopolymer individually. Thus, the weight-average molecular weight of thewater-soluble polymers, including the first PVOH copolymer and thesecond PVOH copolymer, can be in a range of about 30,000 to about175,000, or about 30,000 to about 100,000, or about 55,000 to about80,000, for example. When referring to average viscosity of the PVOHpolymer blend, the weighted natural log average viscosity (μ) is used.The μ for a PVOH polymer that includes two or more PVOH polymers iscalculated by the formula μ=e^(ΣW) ^(i) ^(·ln μ) ^(i) where μ_(i) is theviscosity for the respective PVOH polymers.

In embodiments wherein the water-soluble fiber includes a blend of apolyvinyl alcohol homopolymer and a polyvinyl alcohol copolymer, therelative amounts of homopolymer and copolymer are not particularlylimited. The polyvinyl alcohol homopolymer can make up about 15 wt. % toabout 70 wt. % of total weight of the water-soluble polymer blend, forexample, at least about 15 wt. %, at least about 20 wt. %, at leastabout 25 wt. %, at least about 30 wt. %, at least about 40 wt. %, atleast about 50 wt. %, or at least about 60 wt. % and up to about 70 wt.%, up to about 60 wt. %, up to about 50 wt. %, up to about 40 wt. %, orup to about 30 wt. %, based on the total weight of the water-solublepolymer blend, and can be a single homopolymer or a blend of one or morehomopolymers (e.g., having a difference in viscosity and/or degree ofhydrolysis). The remainder of the water-soluble polymer blend can be thewater-soluble polyvinyl alcohol copolymer. Without intending to be boundby theory, it is believed that as the amount of homopolymer decreasesbelow about 15 wt. %, the ability of the blend of polyvinyl alcoholhomopolymer and copolymer to form a fiber decreases. The water-solublepolyvinyl alcohol copolymer can make up about 30 wt. % to about 85 wt. %of the total weight of the water-soluble polymer blend, for example, atleast about 30 wt. %, at least about 40 wt. %, at least about 50 wt. %,at least about 60 wt. %, at least about 70 wt. %, at least about 75 wt.%, or at least about 80 wt. %, and up to about 85 wt. %, up to about 80wt. %, up to about 70 wt. %, up to about 60 wt. %, up to about 50 wt. %,or up to about 40 wt. %, based on the total weight of the water-solublepolymer blend, and can be a single copolymer or a blend of one or morecopolymers. The blend can consist of a polyvinyl alcohol homopolymer anda polyvinyl alcohol copolymer. The blend can consist of a polyvinylalcohol homopolymer and a plurality of polyvinyl alcohol copolymers. Theblend can consist of more than one polyvinyl alcohol homopolymer andmore than one polyvinyl alcohol copolymer.

In embodiments, the fibers comprise polyvinyl acetate, a polyvinylalcohol homopolymer, a polyvinyl alcohol copolymer, a modified polyvinylalcohol copolymer, or a combination thereof. In embodiments, the fiberscomprise a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer,a modified polyvinyl alcohol copolymer, or a combination thereof. Inembodiments, the fibers comprise a polyvinyl alcohol homopolymer. Inembodiments, the fibers comprise a polyvinyl alcohol copolymer. Inembodiments, the fibers comprise a polyvinyl alcohol copolymer includingan anionic monomer unit (moiety). In embodiment, the fibers comprise ananionic monomer unit and the anionic monomer unit comprises acarboxylate, a sulfonate, or a combination thereof. In embodiments, thepolyvinyl alcohol polymer is water-soluble prior to admixing the fiberwith the modification agent. In embodiments, the polyvinyl alcoholpolymer has a degree of modification in a range of about 0 mol % toabout 10 mol %, prior to the addition of the modification agent. Inembodiments, the polymer in the fiber before modification with themodification agent has a degree of hydrolysis greater than about 79% andless than about 99.99% (e.g., from about 79% to about 96% or from about88% to about 99.99%), prior to admixing the fiber with the hydrolysisagent solution.

The fibers of the disclosure can include water-soluble polymers otherthan PVOH, a PVOH copolymer, and a modified PVOH copolymer, including,without limitation, polyacrylate, water-soluble acrylate copolymer,polyvinyl pyrrolidone, polyethylenimine, pullulan, water-soluble naturalpolymer including, but not limited to, guar gum, gum Acacia, xanthangum, carrageenan, and water-soluble starch, water-soluble polymerderivatives including, but not limited to, modified starches,ethoxylated starch, and hydroxypropylated starch, copolymers of theforegoing and a combination of any of the foregoing additional polymersor copolymers. Yet other water-soluble polymers can include polyalkyleneoxides, polyacrylamides, polyacrylic acids and salts thereof,water-soluble celluloses, cellulose ethers, cellulose esters, celluloseamides, polyvinyl acetates, polycarboxylic acids and salts thereof,polyamino acids, polyamides, gelatins, methylcelluloses,carboxymethylcelluloses and salts thereof, dextrins, ethylcelluloses,hydroxyethyl celluloses, hydroxypropyl methylcelluloses, maltodextrins,polymethacrylates, and combinations of any of the foregoing. Suchwater-soluble polymers, whether PVOH or otherwise, are commerciallyavailable from a variety of sources.

In embodiments, the fiber includes the polyvinyl alcohol polymer and anadditional polymer comprising a polyvinyl alcohol, a polyvinyl acetate,a polyacrylate, a water-soluble acrylate copolymer, a polyvinylpyrrolidone, a polyethylenimine, a pullulan, a guar gum, a gum Acacia, axanthan gum, a carrageenan, a starch, a modified starch, a polyalkyleneoxide, a polyacrylamide, a polyacrylic acid, a cellulose, a celluloseether, a cellulose ester, a cellulose amide, a polycarboxylic acid, apolyamino acid, a polyamide, a gelatin, dextrin, copolymers of theforegoing, and a combination of any of the foregoing additional polymersor copolymers.

The fibers can additionally include a water-insoluble fiber formingmaterial. Suitable water-insoluble fiber forming materials include, butare not limited to, cotton, polyester, copolyester, polyethylene (e.g.,high density polyethylene and low density polyethylene), polypropylene,wood pulp, fluff pulp, abaca, viscose, insoluble cellulose, insolublestarch, hemp, jute, flax, ramie, sisal, bagasse, banana fiber, lacebark,silk, sinew, catgut, wool, sea silk, mohair, angora, cashmere, collagen,actin, nylon, Dacron, rayon, bamboo fiber, modal, diacetate fiber,triacetate fiber, polyester, copolyester, polylactide (PLA),polyethylene terephthalate (PET), polypropylene (PP), and combinationsthereof. In embodiments, the water-insoluble fiber does not includecotton or rayon. In embodiments, the water-insoluble fiber compriseswool, diacetate, triacetate, nylon, PLA, PET, PP, or a combinationthereof.

The fibers can further comprise non-fiber forming materials, referred toherein as auxiliary or secondary ingredients. Auxiliary agents caninclude active agents and processing agents such as, but not limited toactive agents, plasticizers, plasticizer compatibilizers, surfactants,lubricants, release agents, fillers, extenders, cross-linking agents,antiblocking agents, antioxidants, detackifying agents, antifoams,nanoparticles such as layered silicate-type nanoclays (e.g., sodiummontmorillonite), bleaching agents (e.g., sodium metabisulfite, sodiumbisulfite or others), aversive agents such as bitterants (e.g.,denatonium salts such as denatonium benzoate, denatonium saccharide, anddenatonium chloride; sucrose octaacetate; quinine; flavonoids such asquercetin and naringen; and quassinoids such as quassin and brucine) andpungents (e.g., capsaicin, piperine, allyl isothiocyanate, andresinferatoxin), and other functional ingredients, in amounts suitablefor their intended purposes. As used herein and unless specifiedotherwise, “auxiliary agents” include secondary additives, processingagents, and active agents. Specific such auxiliary agents and processingagents can be selected from those suitable for use in water-solublefibers, water-insoluble fibers, nonwoven webs, or those suitable for usein water-soluble films.

In embodiments, the fibers of the disclosure are free of auxiliaryagents. As used herein and unless specified otherwise, “free ofauxiliary agents” with respect to the fiber means that the fiberincludes less than about 0.01 wt %, less than about 0.005 wt. %, or lessthan about 0.001 wt. % of auxiliary agents, based on the total weight ofthe fiber.

A plasticizer is a liquid, solid, or semi-solid that is added to amaterial (usually a resin or elastomer) making that material softer,more flexible (by decreasing the glass-transition temperature of thepolymer), and easier to process. A polymer can alternatively beinternally plasticized by chemically modifying the polymer or monomer.In addition or in the alternative, a polymer can be externallyplasticized by the addition of a suitable plasticizing agent. Water isrecognized as a very efficient plasticizer for PVOH and other polymers,including but not limited to water-soluble polymers; however, thevolatility of water makes its utility limited since polymer films needto have at least some resistance (robustness) to a variety of ambientconditions including low and high relative humidity.

The plasticizer can include, but is not limited to, glycerin,diglycerin, sorbitol, ethylene glycol, diethylene glycol, triethyleneglycol, dipropylene glycol, tetraethylene glycol, propylene glycol,polyethylene glycols up to 400 MW, neopentyl glycol, trimethylolpropane,polyether polyols, sorbitol, 2-methyl-1,3-propanediol (MPDiol®),ethanolamines, and a mixture thereof. The total amount of the non-waterplasticizer provided in a fiber can be in a range of about 1 wt. % toabout 45 wt. %, or about 5 wt. % to about 45 wt. %, or about 10 wt. % toabout 40 wt. %, or about 20 wt. % to about 30 wt. %, about 1 wt. % toabout 4 wt. %, or about 1.5 wt. % to about 3.5 wt. %, or about 2.0 wt. %to about 3.0 wt. %, for example about 1 wt. %, about 2.5 wt. %, about 5wt. %, about 10 wt. %, about 15 wt. %, about 20 wt. %, about 25 wt. %,about 30 wt. %, about 35 wt. %, or about 40 wt. %, based on total fiberweight.

Surfactants for use in fibers are well known in the art. Surfactants foruse in films are also well known in the art and can suitably be used inthe fibers and/or nonwoven webs of the disclosure. Optionally,surfactants are included to aid in the dispersion of the fibers duringcarding. Suitable surfactants for fibers of the present disclosureinclude, but are not limited to, dialkyl sulfosuccinates, lactylatedfatty acid esters of glycerol and propylene glycol, lactylic esters offatty acids, sodium alkyl sulfates, polysorbate 20, polysorbate 60,polysorbate 65, polysorbate 80, alkyl polyethylene glycol ethers,lecithin, acetylated fatty acid esters of glycerol and propylene glycol,sodium lauryl sulfate, acetylated esters of fatty acids, myristyldimethylamine oxide, trimethyl tallow alkyl ammonium chloride,quaternary ammonium compounds, alkali metal salts of higher fatty acidscontaining about 8 to 24 carbon atoms, alkyl sulfates, alkylpolyethoxylate sulfates, alkylbenzene sulfonates, monoethanolamine,lauryl alcohol ethoxylate, propylene glycol, diethylene glycol, saltsthereof and combinations of any of the forgoing.

Suitable surfactants can include the nonionic, cationic, anionic andzwitterionic classes. Suitable surfactants include, but are not limitedto, propylene glycols, diethylene glycols, monoethanolamine,polyoxyethylenated polyoxypropylene glycols, alcohol ethoxylates,alkylphenol ethoxylates, tertiary acetylenic glycols and alkanolamides(nonionics), polyoxyethylenated amines, quaternary ammonium salts andquaternized polyoxyethylenated amines (cationics), alkali metal salts ofhigher fatty acids containing about 8 to 24 carbon atoms, alkylsulfates, alkyl polyethoxylate sulfates and alkylbenzene sulfonates(anionics), and amine oxides, N-alkylbetaines and sulfobetaines(zwitterionics). Other suitable surfactants include dioctyl sodiumsulfosuccinate, lactylated fatty acid esters of glycerin and propyleneglycol, lactylic esters of fatty acids, sodium alkyl sulfates,polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80,lecithin, acetylated fatty acid esters of glycerin and propylene glycol,and acetylated esters of fatty acids, and combinations thereof. Invarious embodiments, the amount of surfactant in the fiber is in a rangeof about 0.01 wt. %, to about 2.5 wt. %, about 0.1 wt. % to about 2.5wt. %, about 1.0 wt. % to about 2.0 wt. %, about 0.01 wt % to 0.25 wt %,or about 0.10 wt % to 0.20 wt %.

In embodiments, the fibers and/or nonwoven webs of the disclosure caninclude an active agent. The active agent can be added to the fiberitself, or during carding of the nonwoven web, and/or can be added tothe nonwoven web prior to bonding. Active agents added to the fibersduring carding can be distributed throughout the nonwoven web. Activeagents added to the nonwoven web after carding but prior to bonding canbe selectively added to one or both faces of the nonwoven web.Additionally, active agents can be added to the surface of pouches orother articles prepared from the nonwoven webs. In embodiments, theactive agent is provided as part of the plurality of fibers, dispersedwithin the nonwoven web, provided on a face of the nonwoven web, or acombination thereof.

The active agent, when present in the fiber and/or nonwoven web in anamount of at least about 1 wt %, or in a range of about 1 wt % to about99 wt %, provides additional functionality to the nonwoven web. Inembodiments, the active agent can comprise one or more componentsincluding, but not limited to, enzymes, oils, flavors, colorants, odorabsorbers, fragrances, pesticides, fertilizers, activators, acidcatalysts, metal catalysts, ion scavengers, detergents, disinfectants,surfactants, bleaches, bleach components, fabric softeners orcombinations thereof. In embodiments, the active agent can comprise acolorant, a surfactant, or a combination thereof. The active agent cantake any desired form, including as a solid (e.g., powder, granulate,crystal, flake, or ribbon), a liquid, a mull, a paste, a gas, etc., andoptionally can be encapsulated.

In certain embodiments, the active agent may comprise an enzyme.Suitable enzymes include enzymes categorized in any one of the sixconventional Enzyme Commission (EC) categories, i.e., theoxidoreductases of EC 1 (which catalyze oxidation/reduction reactions),the transferases of EC 2 (which transfer a functional group, e.g., amethyl or phosphate group), the hydrolases of EC 3 (which catalyze thehydrolysis of various bonds), the lyases of EC 4 (which cleave variousbonds by means other than hydrolysis and oxidation), the isomerases ofEC 5 (which catalyze isomerization changes within a molecule) and theligases of EC 6 (which join two molecules with covalent bonds). Examplesof such enzymes include dehydrogenases and oxidases in EC 1,transaminases and kinases in EC 2, lipases, cellulases, amylases,mannanases, and peptidases (a.k.a. proteases or proteolytic enzymes) inEC 3, decarboxylases in EC 4, isomerases and mutases in EC 5 andsynthetases and synthases of EC 6. Suitable enzymes from each categoryare described in, for example, U.S. Pat. No. 9,394,092, the entiredisclosure of which is herein incorporated by reference.

Enzymes for use in laundry and dishwashing applications can include oneor more of protease, amylase, lipase, dehydrogenase, transaminase,kinase, cellulase, mannanase, peptidase, decarboxylase, isomerase,mutase, synthetase, synthase, and oxido-reductase enzymes, includingoxido-reductase enzymes that catalyze the formation of bleaching agents.

Oils other than fragrances can include flavorants and colorants.

In one class of embodiments the active agent includes a flavor orcombination of flavors. Suitable flavors include but are not limited to,spearmint oil, cinnamon oil, oil of wintergreen (methylsalicylate),peppermint oils, and synthetic and natural fruit flavors, includingcitrus oils.

In some embodiments, the active agent may be a colorant or combinationof colorants. Examples of suitable colorants include food colorings,caramel, paprika, cinnamon, and saffron. Other examples of suitablecolorants can be found in U.S. Pat. No. 5,002,789, hereby incorporatedby reference in its entirety.

Another class of embodiments include one or more odor absorbers asactive agents. Suitable odor absorbers for use as active agentsaccording to the disclosure include, but are not limited to, zeolites,and complex zinc salts of ricinoleic acid. The odor absorbing activeagent can also comprise fixatives that are well known in the art aslargely odor-neutral fragrances, including but not limited to extractsof labdanum, styrax, and derivatives of abietic acid.

Another class of embodiments include one or more fragrances as activeagents. As used herein, the term fragrance refers to any applicablematerial that is sufficiently volatile to produce a scent. Embodimentsincluding fragrances as active agents can include fragrances that arescents pleasurable to humans, or alternatively fragrances that arescents repellant to humans, animals, and/or insects. Suitable fragrancesinclude, but are not limited to, fruits including, but not limited to,lemon, apple, cherry, grape, pear, pineapple, orange, strawberry,raspberry, musk and flower scents including, but not limited to,lavender-like, rose-like, iris-like and carnation-like. Optionally thefragrance is one that is not also a flavoring. Other fragrances includeherbal scents including, but not limited to, rosemary, thyme, and sage;and woodland scents derived from pine, spruce and other forest smells.Fragrances may also be derived from various oils, including, but notlimited to, essential oils, or from plant materials including, but notlimited to, peppermint, spearmint and the like. Suitable fragrant oilscan be found in U.S. Pat. No. 6,458,754, hereby incorporated byreference in its entirety.

Fragrances can include perfumes. The perfume may comprise neat perfume,encapsulated perfume, or mixtures thereof. Preferably, the perfumeincludes neat perfume. A portion of the perfume may be encapsulated in acore-shell encapsulate. In another type of embodiment, the perfume willnot be encapsulated in a core/shell encapsulate.

As used herein, the term “perfume” encompasses the perfume raw materials(PRMs) and perfume accords. The term “perfume raw material” as usedherein refers to compounds having a molecular weight of at least about100 g/mol and which are useful in imparting an odor, fragrance, essenceor scent, either alone or with other perfume raw materials. As usedherein, the terms “perfume ingredient” and “perfume raw material” areinterchangeable. The term “accord” as used herein refers to a mixture oftwo or more PRMs.

Applicable insect repellant fragrances include one or more ofdichlorvos, pyrethrin, allethrin, naled and/or fenthion pesticidesdisclosed in U.S. Pat. No. 4,664,064, incorporated herein by referencein its entirety. Suitable insect repellants are citronellal(3,7-dimethyl-6-octanal), N,N-diethyl-3-methylbenzamide (DEET),vanillin, and the volatile oils extracted from turmeric (Curcuma longa),kaffir lime (Citrus hystrix), citronella grass (Cymbopogon winterianus)and hairy basil (Ocimum americanum). Moreover, applicable insectrepellants can be mixtures of insect repellants.

In one class of embodiments, the active agents according to thedisclosure can comprise one or more pesticides. Suitable pesticides mayinclude, but are not limited to, insecticides, herbicides, acaricides,fungicides, and larvacides.

Another class of embodiments include one or more fertilizers as activeagents. As used herein, the term fertilizer applies to any applicablematerial that releases one or more of nitrogen, phosphorus, potassium,calcium, magnesium, sulfur, boron, chlorine, copper, iron, manganese,molybdenum, or zinc. Suitable fertilizers include, but are not limitedto zeolites. For example, clinoptilolite is a zeolite that releasespotassium and can also release nitrogen when preloaded with ammonium.

One class of embodiments comprise acid catalysts as active agents. Asused herein, the term acid catalysts refers to any species that servesas a proton source, thereby facilitating a chemical reaction. In onetype of embodiment, the acid catalyst will be a non-oxidizing organicacid. A suitable organic acid is para-toluenesulfonic acid. In someembodiments, active agents that are acid catalysts will facilitatereactions including, but not limited to, acetalization, esterificationor transesterification. Additional acid catalyzed reactions are wellknown in the art.

In one class of embodiments, active agents will include metal catalysts.These catalysts mediate reactions including, but not limited to,oxidation or reduction, hydrogenation, carbonylation, C—H bondactivation, and bleaching. Suitable metals for use as metal catalystsinclude, but are not limited to the VIIIA and IB transition metals, forexample, iron, cobalt, nickel, copper, platinum, rhodium, ruthenium,silver, osmium, gold and iridium. The metal that mediates catalysis canbe of any suitable oxidation state.

In alternative embodiments, the active agent may optionally be an ionscavenger. Suitable ion scavengers include, but are not limited to,zeolites. Optionally, zeolites can be added to water-soluble packetscomprising laundry detergents or dish washing detergents enclosedwithin, as a water softener.

Inorganic and organic bleaches are suitable cleaning active agents foruse herein. Inorganic bleaches include perhydrate salts including, butnot limited to, perborate, percarbonate, perphosphate, persulfate andpersilicate salts. The inorganic perhydrate salts are normally thealkali metal salts. Alkali metal percarbonates, particularly sodiumpercarbonate are suitable perhydrates for use herein. Organic bleachescan include organic peroxyacids including diacyl and tetraacylperoxides,especially, but not limited to, diperoxydodecanedioc acid,diperoxytetradecanedioc acid, and diperoxyhexadecanedioc acid. Dibenzoylperoxide is a suitable organic peroxyacid according to the disclosure.Other organic bleaches include the peroxy acids, particular examplesbeing the alkylperoxy acids and the arylperoxy acids.

In one class of embodiments, active agents can comprise bleachsensitizers, including organic peracid precursors that enhance thebleaching action in the course of cleaning at temperatures of 60° C. andbelow. Bleach sensitizers suitable for use herein include compoundswhich, under perhydrolysis conditions, give aliphatic peroxoycarboxylicacids having from 1 to 10 carbon atoms, or from 2 to 4 carbon atoms,and/or optionally substituted perbenzoic acid. Suitable substances bearO-acyl and/or N-acyl groups of the number of carbon atoms specifiedand/or optionally substituted benzoyl groups. Suitable substancesinclude, but are not limited to, polyacylated alkylenediamines, inparticular tetraacetylethylenediamine (TAED), acylated triazinederivatives, in particular1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylatedglycolurils, in particular tetraacetylglycoluril (TAGU), N-acylimides,in particular N-nonanoylsuccinimide (NOSI), acylated phenolsulfonates,in particular n-nonanoyl- or isononanoyloxybenzenesulfonate (n- oriso-NOBS), carboxylic anhydrides, in particular phthalic anhydride,acylated polyhydric alcohols, in particular triacetin, ethylene glycoldiacetate and 2,5-diacetoxy-2,5-dihydrofuran and also triethylacetylcitrate (TEAC).

In embodiments that comprise fabric softeners as active agents, variousthrough-the-wash fabric softeners, especially the impalpable smectiteclays of U.S. Pat. No. 4,062,647, incorporated herein by reference inits entirety, as well as other softener clays known in the art, canoptionally be used to provide fabric softener benefits concurrently withfabric cleaning. Clay softeners can be used in combination with amineand cationic softeners as disclosed, for example, in U.S. Pat. Nos.4,375,416 and 4,291,071, incorporated herein by reference in theirentireties.

In embodiments, the active agent can include disinfectants.Disinfectants suitable for use herein can include, but are not limitedto, hydrogen peroxide, inorganic peroxides and precursors thereof,sodium metabisulfite, quaternary ammonium cation based compounds,chlorine, activated carbon, and hypochlorite.

In embodiments, the active agent can include surfactants. Suitablesurfactants for use herein can include, but are not limited to,propylene glycols, diethylene glycols, monoethanolamine,polyoxyethylenated polyoxypropylene glycols, alcohol ethoxylates,alkylphenol ethoxylates, tertiary acetylenic glycols and alkanolamides(nonionics), polyoxyethylenated amines, quaternary ammonium salts andquaternized polyoxyethylenated amines (cationics), alkali metal salts ofhigher fatty acids containing about 8 to 24 carbon atoms, alkylsulfates, alkyl polyethoxylate sulfates and alkylbenzene sulfonates(anionics), amine oxides, N-alkylbetaines and sulfobetaines(zwitterionics), dioctyl sodium sulfosuccinate, lactylated fatty acidesters of glycerin and propylene glycol, lactylic esters of fatty acids,sodium alkyl sulfates, polysorbate 20, polysorbate 60, polysorbate 65,polysorbate 80, lecithin, acetylated fatty acid esters of glycerin andpropylene glycol, and acetylated esters of fatty acids, and combinationsthereof.

Active agents may be solids or liquids. Active agents that are solidscan have an average particle size (e.g., Dv50) of at least about 0.01μm, or a size in a range of about 0.01 μm to about 2 mm, for example.Liquid active agents may be applied directly to the nonwoven web, mixedwith a carrier powder, or microencapsulated. In embodiments thatcomprise a carrier powder, the average particle size of the carrierpowder can be at least about 0.01 μm, or in a range of about 0.01 μm toabout 2 mm, for example.

In one class of embodiments the active agent is encapsulated, allowingfor the controlled release of the active agent. Suitable microcapsulescan include or be made from one or more of melamine formaldehyde,polyurethane, urea formaldehyde, chitosan, polymethyl methacrylate,polystyrene, polysulfone, poly tetrahydrofuran, gelatin, gum arabic,starch, polyvinyl pyrrolidone, carboxymethylcellulose,hydroxyethylcellulose, methylcellulose, arabinogalactan, polyvinylalcohol, polyacrylic acid, ethylcellulose, polyethylene,polymethacrylate, polyimide, poly (ethylenevinyl acetate), cellulosenitrate, silicones, poly(lactideco-glycolide), paraffin, carnauba,spermaceti, beeswax, stearic acid, stearyl alcohol, glyceryl stearates,shellac, cellulose acetate phthalate, zein, and combinations thereof. Inone type of embodiment, the microcapsule is characterized by a meanparticle size (e.g., Dv50) of at least about 0.1 micron, or in a rangeof about 0.1 micron to about 200 microns, for example. In alternateembodiments, the microcapsules can form agglomerates of individualparticles, for example wherein the individual particles have a meanparticle size of at least about 0.1 micron, or in a range of about 0.1micron to about 200 microns.

The fibers to be treated can be formed by any process known in the art,for example, wet cool gel spinning, thermoplastic fiber spinning, meltblowing, spun bonding, electro-spinning, rotary spinning, continuousfilament producing operations, tow fiber producing operations, andcombinations thereof.

In embodiments, the fibers comprise fibers formed by wet cool gelspinning, melt blowing, spun bonding, or a combination thereof. Inembodiments, the fibers comprise fibers that are formed by wet cool gelspinning. In embodiments, the fibers comprise water-soluble fibers andnonwoven webs prepared therefrom are formed in a continuous melt blownprocess. In embodiments, the fibers comprise water-soluble fibers andnonwoven webs prepared therefrom are formed in a continuous spun bondprocess. It is standard in the art to refer to fibers and nonwoven websby the process used to prepare the same. Thus, any reference herein to,for example, a “melt blown fiber” or a “carded nonwoven web” should notbe understood to be a product-by-process limitation for a particularmelt blown or carding method, but rather merely identifying a particularfiber or web. Processing terms may therefore be used to distinguishfibers and/or nonwovens, without limiting the recited fiber and/ornonwoven to preparation by any specific process.

The fibers to be treated can be formed as bicomponent fibers. As usedherein, and unless specified otherwise, “bicomponent fibers” do notrefer to a fiber including a blend of fiber forming materials but,rather, refer to fibers including two or more distinct regions of fiberforming materials, wherein the composition of the fiber formingmaterials differ by region. Examples of bicomponent fibers include, butare not limited to, core-sheath bicomponent fibers, island in the seabicomponent fibers, and side-by-side bicomponent fibers. Core-sheathbicomponent fibers generally include a core having a first compositionof fiber forming materials (e.g., a single fiber forming material or afirst blend of fiber forming materials) and a sheath having a secondcomposition of fiber forming materials (e.g., a single fiber formingmaterial that is different from the core material, or a second blend offiber forming materials that is different from the first blend of fiberforming materials of the core). Island in the sea bicomponent fibersgenerally include a first, continuous, “sea” region having a firstcomposition of fiber forming materials and discreet “island” regionsdispersed therein having a second composition of fiber forming materialsthat is different from the first composition. Side-by-side bicomponentfibers generally include a first region running the length of the fiberand including a first composition of fiber forming materials adjacent toat least a second region running the length of the fiber and includingsecond composition of fiber forming materials that is different from thefirst composition. Such bicomponent fibers are well known in the art.

The shape of the fiber is not particularly limited and can havetransverse cross-sectional shapes including, but is not limited to,round, oval (also referred to as ribbon), triangular (also referred toas delta), trilobal, and/or other multi-lobal shapes. (FIG. 1). It willbe understood that the shape of the fiber need not be perfectlygeometric, for example, a fiber having a round transversecross-sectional shape need not have a perfect circle as the transversecross-sectional area, and a fiber having a triangular transversecross-sectional shape generally has rounded corners.

It will be understood that the diameter of a fiber refers to thetransverse cross-section diameter of the fiber along the longesttransverse cross-sectional axis. When a fiber is described as having (ornot having) a particular diameter, unless specified otherwise, it isintended that the specified diameter is the average diameter for thespecific fiber type referenced, i.e., a plurality of fibers preparedfrom polyvinyl alcohol fiber forming material has an arithmetic averagefiber diameter over the plurality of fibers. For shapes not typicallyconsidered to have a “diameter”, e.g., a triangle or a multi-lobalshape, the diameter refers to the diameter of a circle circumscribingthe fiber shape (FIG. 1).

The fibers of the disclosure typically have a diameter in a range ofabout 10 micron to 300 micron, for example, at least 10 micron, at least15 micron, at least 20 micron, at least 25 micron, at least 50 micron,at least 100 micron, or at least 125 micron and up to about 300 micron,up to about 275 micron, up to about 250 micron, up to about 225 micron,up to about 200 micron, up to about 100 micron, up to about 50 micron,up to about 45 micron, up to about 40 micron, or up to about 35 micronfor example in a range of about 10 micron to about 300 micron, about 50micron to about 300 micron, about 100 micron to about 300 micron, about10 micron to about 50 micron, about 10 micron to about 45 micron, orabout 10 micron to about 40 micron. In embodiments, the fibers can havea diameter greater than 100 micron to about 300 micron. In embodiments,the fibers comprise cellulose and have a diameter in a range of about 10micron to about 50 micron, about 10 micron to about 30 micron, about 10micron to about 25 micron, about 10 micron to about 20 micron, or about10 micron to about 15 micron. In embodiments, the fibers comprise awater-soluble fiber forming material and have a diameter of about 50micron to about 300 micron, about 100 micron to about 300 micron, about150 micron to about 300 micron, or about 200 micron to about 300 micron.In embodiments, the diameters of a plurality of the water-soluble fibersused to prepare a nonwoven web of the disclosure have diameters that aresubstantially uniform. As used herein, fiber diameters are“substantially uniform” if the variance in diameter between fibers isless than 10%, for example 8% or less, 5% or less, 2% or less, or 1% orless. Fibers having substantially uniform diameters can be prepared by awet cooled gel spinning process or a thermoplastic fiber spinningprocess. Further, when a blend of fiber types are used, the averagediameter of the fiber blend can be determined using a weighted averageof the individual fiber types.

The fibers of the disclosure can generally be of any length. Inembodiments, the length of the fibers can be in a range of about 20 mmto about 100 mm, about 20 to about 90, about 30 mm to about 80 mm, about10 mm to about 60 mm, or about 30 mm to about 60 mm, for example, atleast about 30 mm, at least about 35 mm, at least about 40 mm, at leastabout 45 mm, or at least about 50 mm, and up to about 100 mm, up toabout 95 mm, up to about 90 mm, up to about 80 mm, up to about 70 mm, orup to about 60 mm. In embodiments, the length of the fibers can be lessthan about 30 mm or in a range of about 0.25 mm to less than about 30mm, for example, at least about 0.25 mm, at least about 0.5 mm, at leastabout 0.75 mm, at least about 1 mm, at least about 2.5 mm, at leastabout 5 mm, at least about 7.5 mm, or at least about 10 mm and up toabout 29 mm, up to about 28 mm, up to about 27 mm, up to about 26 mm, upto about 25 mm, up to about 20 mm, or up to about 15 mm. The fibers canbe prepared to any length by cutting and/or crimping an extruded polymermixture. In embodiments, the fiber can be a continuous filament, forexample, prepared by processes such as spun bonding, melt blowing,electro-spinning, and rotary spinning wherein a continuous filament isprepared and provided directly into a web form. Further, when a blend offiber types are used, the average length of the fibers can be determinedusing a weighted average of the individual fiber types.

The fibers of the disclosure can generally have any length to diameter(L/D) ratio. In embodiments, length to diameter ratio of the fibers canbe greater than about 2, greater than about 3, greater than about 4,greater than about 6, greater than about 10, greater than about 50,greater than about 60, greater than about 100, greater than about 200,greater than about 300, greater than about 400, or greater than about1000. Advantageously, the tactility of a nonwoven web can be controlledusing the L/D ratio of the fibers and the respective amounts of fibershaving various L/D ratios in the nonwoven composition. In general, asthe L/D of the fiber decreases, the stiffness and resistance to bendingincreases, providing a rougher hand feel. The fibers of the disclosuregenerally impart a rough feel to a nonwoven web including same, when thefibers have a low L/D ratio in a range of about 0.5 to about 15, orabout 0.5 to about 25, or about 1 to about 5. Such low L/D fibers can beprovided in a nonwoven web in an amount in a range of about 0 to about50% by weight, based on the total weight of the fibers in the nonwovenweb, for example, in a range of about 0.5 wt. % to about 25 wt. %, orabout 1 wt. % to about 15 wt. %. If the amount of low L/D fibers in anonwoven web is not known, the amount can be estimated by visualinspection of a micrograph of a nonwoven web. As shown in FIG. 4, thepopulation of fibers having a visibly larger diameter and shorter cutrate, based on the total fiber population can be observed. FIG. 4A is amicrograph of a nonwoven web having 0% of low L/D fibers and a softnessrating of 1, whereas FIG. 4B is a micrograph of a nonwoven web having25% of low L/D fibers and a softness rating of 5.

The fibers of the disclosure can generally have any tenacity. Thetenacity of the fiber correlates to the coarseness of the fiber. Ingeneral, as the tenacity of the fiber decreases the coarseness of thefiber increases. Fibers of the disclosure can have a tenacity in a rangeof about 1 to about 100 cN/dtex, or about 1 to about 75 cN/dtex, orabout 1 to about 50 cN/dtex, or about 1 to about 45 cN/dtex, or about 1to about 40 cN/dtex, or about 1 to about 35 cN/dtex, or about 1 to about30 cN/dtex, or about 1 to about 25 cN/dtex, or about 1 to about 20cN/dtex, or about 1 to about 15 cN/dtex, or about 1 to about 10 cN/dtex,or about 1 to about 5 cN/dtex, or about 3 to about 8 cN/dtex, or about 4to about 8 cN/dtex, or about 6 to about 8 cN/dtex, or about 4 to about 7cN/dtex, or about 10 to about 20, or about 10 to about 18, or about 10to about 16, or about 1 cN/dtex, about 2 cN/dtex, about 3 cN/dtex, about4 cN/dtex, about 5 cN/dtex, about 6 cN/dtex, about 7 cN/dtex, about 8cN/dtex, about 9 cN/dtex, about 10 cN/dtex, about 11 cN/dtex, about 12cN/dtex, about 13 cN/dtex, about 14 cN/dtex, or about 15 cN/dtex. Inembodiments, the fibers can have a tenacity of about 3 cN/dtex to about10 cN/dtex. In embodiments, the fibers can have a tenacity of about 7cN/dtex to about 10 cN/dtex. In embodiments, the fibers can have atenacity of about 4 cN/dtex to about 8 cN/dtex. In embodiments, thefibers can have a tenacity of about 6 cN/dtex to about 8 cN/dtex.

The fibers of the disclosure can generally have any fineness. Thefineness of the fiber correlates to how many fibers are present in atransverse cross-section of a yarn of a given thickness. Fiber finenessis the ratio of fiber mass to length. The main physical unit of fiberfineness is 1 tex, which is equal to 1000 m of fiber weighing 1 g.Typically, the unit dtex is used, representing 1 g/10,000 m of fiber.The fineness of the fiber can be selected to provide a nonwoven webhaving suitable stiffness/hand-feel of the nonwoven web, torsionalrigidity, reflection and interaction with light, absorption of dyeand/or other actives/additives, ease of fiber spinning in themanufacturing process, and uniformity of the finished article. Ingeneral, as the fineness of the fibers increases the nonwovens resultingtherefrom demonstrate higher uniformity, improved tensile strengths,extensibility and luster. Additionally, without intending to be bound bytheory it is believed that finer fibers will lead to slower dissolutiontimes as compared to larger fibers based on density. Further, withoutintending to be bound by theory, when a blend of fibers is used, theaverage fineness of the fibers can be determined using a weightedaverage of the individual fiber components. Fibers can be characterizedas very fine (dtex 1.22), fine (1.22 dtex 1.54), medium (1.54 dtex1.93), slightly coarse (1.93 dtex 2.32), and coarse (dtex 2.32). Thenonwoven web of the disclosure can include fibers that are very fine,fine, medium, slightly coarse, or a combination thereof. In embodiments,the fibers have a fineness in a range of about 1 dtex to about 10 dtex,about 1 dtex to about 7 dtex, about 1 dtex to about 5 dtex, about 1 dtexto about 3 dtex, or about 1.7 dtex to about 2.2 dtex. In embodiments,fibers have a fineness of about 1.7 dtex. In embodiments, fibers have afineness of about 2.2 dtex.

Wet Cooled Gel Spinning

In embodiments, the fibers of the disclosure are formed according to awet cooled gel spinning process, the wet cooled gel spinning processincluding the steps of

(a) dissolving the fiber forming material (polymers) in solution to forma polymer mixture, the polymer mixture optionally including auxiliaryagents;(b) extruding the polymer mixture through a spinneret nozzle to asolidification bath to form an extruded polymer mixture;(c) passing the extruded polymer mixture through a solvent exchangebath;(d) optionally wet drawing the extruded polymer mixture; and(e) finishing the extruded polymer mixture to provide the fibers.

The solvent in which the fiber forming polymer is dissolved can suitablybe any solvent in which the polymer is soluble. In embodiments, thesolvent in which the polymer is dissolved includes a polar aproticsolvent. In embodiments, the solvent in which the polymer is dissolvedincludes dimethyl sulfoxide (DMSO).

In general, the solidification bath includes a cooled solvent forgelling the extruded polymer mixture. The solidification bath cangenerally be at any temperature that facilitates solidification of theextruded polymer mixture. The solidification bath can include a mixtureof a solvent in which the polymer is soluble and a solvent in which thepolymer is not soluble. The solvent in which the polymer is not solubleis generally the primary solvent, wherein the solvent in which thepolymer is not soluble makes up greater than 50% of the mixture.

After passing through the solidification bath, the extruded polymermixture gel can be passed through one or more solvent replacement baths.The solvent replacement baths are provided to replace the solvent inwhich the polymer is soluble with the solvent in which the polymer isnot soluble to further solidify the extruded polymer mixture and replacethe solvent in which the polymer is soluble with a solvent that willmore readily evaporate, thereby reducing the drying time. Solventreplacement baths can include a series of solvent replacement bathshaving a gradient of solvent in which the polymer is soluble with thesolvent in which the polymer is not soluble, a series of solventreplacement baths having only the solvent in which the polymer is notsoluble, or a single solvent replacement bath having only the solvent inwhich the polymer is not soluble.

Finished fibers are sometimes referred to as staple fibers, shortcutfibers, or pulp. In embodiments, finishing includes drying the extrudedpolymer mixture. In embodiments, finishing includes cutting or crimpingthe extruded polymer mixture to form individual fibers. Wet drawing ofthe extruded polymer mixture provides a substantially uniform diameterto the extruded polymer mixture and, thus, the fibers cut therefrom.Drawing is distinct from extruding, as is well known in the art. Inparticular, extruding refers to the act of making fibers by forcing theresin mixture through the spinneret head whereas drawing refers tomechanically pulling the fibers in the machine direction to promotepolymer chain orientation and crystallinity for increased fiber strengthand tenacity.

In embodiments wherein the fibers are prepared from a wet cooled gelspinning process, the fiber forming polymer can be generally any fiberforming polymer or blend thereof, e.g., two or more different polymers,as generally described herein. In refinements of the foregoingembodiment, the polymer(s) can have any degree of polymerization (DP),for example, in a range of 10 to 10,000,000, for example, at least 10,at least 20, at least 50, at least 100, at least 200, at least 300, atleast 400, at least 500, at least 750, or at least 1000 and up to10,000,000, up to 5,000,000, up to 2,500,00, up to 1,000,000, up to900,000, up to 750,000, up to 500,000, up to 250,000, up to 100,000, upto 90,000, up to 75,000, up to 50,000, up to 25,000, up to 12,000, up to10,000, up to 5,000, or up to 2,500, for example in a range of 1000 toabout 50,000, 1000 to about 25,000, 1000 to about 12,000, 1000 to about5,000, 1000 to about 2,500, about 50 to about 12,000, about 50 to about10,000, about 50 to about 5,000, about 50 to about 2,500, about 50 toabout 1000, about 50 to about 900, about 100 to about 800, about 150 toabout 700, about 200 to about 600, or about 250 to about 500. Inembodiments, the DP is at least 1,000. In embodiments, the fiber formingpolymer comprises a polyvinyl alcohol polymer having a DP in a range of1000 to about 50,000, 1000 to about 25,000, 1000 to about 12,000, 1000to about 5,000, 1000 to about 2,500, about 50 to about 12,000, about 50to about 10,000, about 50 to about 5,000, about 50 to about 2,500, about50 to about 1000, about 50 to about 900, about 100 to about 800, about150 to about 700, about 200 to about 600, or about 250 to about 500. Inembodiments, the fiber forming polymer comprises a polyvinyl alcoholhaving a DP in a range of 1000 to about 50,000, 1000 to about 25,000,1000 to about 12,000, 1000 to about 5,000, or 1000 to about 2,500.

The wet cooled gel spinning process advantageously provides one or morebenefits such as providing a fiber that includes a blend ofwater-soluble polymers, providing control over the diameter of thefibers, providing relatively large diameter fibers, providing controlover the length of the fibers, providing control over the tenacity ofthe fibers, providing high tenacity fibers, providing fibers frompolymers having a large degree of polymerization, and/or providingfibers which can be used to provide a self-supporting nonwoven web.Continuous processes such as spun bond, melt blown, electro-spinning androtary spinning generally do not allow for blending of water-solublepolymers (e.g., due to difficulties matching the melt index of variouspolymers), forming large diameter (e.g., greater than 50 micron) fibers,controlling the length of the fibers, providing high tenacity fibers, orthe use of polymers having a high degree of polymerization. Further, thewet cooled gel spinning process advantageously is not limited topolymers that are only melt processable and, therefore, can accessfibers made from fiber forming materials having very high molecularweights, high melting points, low melt flow index, or a combinationthereof, providing fibers having stronger physical properties anddifferent chemical functionalities compared to fibers prepared by a heatextrusion process.

Methods of preparing staple fibers and continuous fibers are well knownin the art. Once the staple fibers or continuous fibers are carded, thenonwoven web is bonded. Methods of bonding staple fibers are well knownin the art and can include through air bonding (thermal), calendarbonding (thermal with pressure), and chemical bonding. The nonwoven webof the disclosure can be thermally or chemically bonded. The nonwovenweb can be generally porous with varying pore size, morphology and webheterogeneity. Fiber physical properties and the type of bonding canaffect the porosity of the resulting nonwoven web. Calendar bonding isachieved by applying heat and pressure, and typically maintains the poresize, shape, and alignment produced by the carding process. Theconditions for calendar bonding can be readily determined by one ofordinary skill in the art. In general, if the heat and/or pressureapplied is too low, the fibers will not sufficiently bind to form afree-standing web and if the heat and/or pressure is too high, thefibers will begin to meld together. The fiber chemistry dictates theupper and lower limits of heat and/or pressure for calendar bonding.Without intending to be bound by theory, it is believed that attemperatures above 235° C., polyvinyl alcohol based fibers degrade.Methods of embossment for calendar bonding of fibers are known. Theembossing can be a one-sided embossing or a double-sided embossing.Typically, embossing of water-soluble fibers includes one-sidedembossing using a single embossing roll consisting of an orderedcircular array and a steel roll with a plain surface. As embossing isincreased (e.g., as surface features are imparted to the web), thesurface area of the web is increased. Without intending to be bound bytheory it is expected that as the surface are of the web is increased,the solubility of the web is increased. Accordingly, the solubilityproperties of the nonwoven web can be advantageously tuned by changingthe surface area through embossing.

In contrast to calendar bonding, chemical bonding typically uses abinder solution of the waste polymer left over from preparing the fibersto coat the carded fibers under pressure, which can result in smaller,less ordered pores relative to the pores as carded. Generally, thesolvent can be any solvent that solubilizes the binder. Typically, thesolvent of the chemical bonding solution is water. Without intending tobe bound by theory, it is believed that if the polymer solution used forchemical bonding is sufficiently concentrated and/or sufficient pressureis applied, a nonporous water-dispersible nonwoven web can be formed.The solvent used in chemical bonding induces partial solubilization ofthe existing fibers in the web to weld and bond the fibers together. Thepolyvinyl alcohol binder provided in the solution assists in the weldingprocess to provide a more mechanically robust web. The temperature ofthe polymer solution is not particularly limited and can be provided atroom temperature (about 23° C.).

In some embodiments, a second layer of fibers can be used to bond thenonwoven web. Without intending to be bound by theory, it is believedthat fibers prepared from by a melt blown process, for example,water-soluble fibers, can be used to bond the nonwoven web using anin-line process. In particular, a nonwoven web can be passed under amelt blown process station such that the melt blown fibers are depositedafter melt extrusion and as the melt blown fibers cool and solidify,they bond to each other and to the nonwoven web on which they aredeposited. Melt blown fibers can be micro- to nano-scale in length andcan be provided on the nonwoven web such that the melt blown fibers makeup about 15%, about 12%, about 10%, about 8%, about 6%, or about 5%, byweight of the final nonwoven web, based on the total weight of thefibers in the final nonwoven web. Without intending to be bound bytheory it is believed that the inclusion of about 5% to about 15% ofmelt blown fibers can increase the mechanical integrity of the nonwovenweb, without substantially changing the solubility properties of thenonwoven web. In general, when a polyvinyl alcohol fiber formingmaterial is used to prepare a melt blown fiber, the polyvinyl alcoholpolymer will be a homopolymer as melt blown processes require lowviscosity and high melt flow index polymers.

Pore sizes can be determined using high magnification and orderedsurface analysis techniques including, but not limited toBrunauer-Emmett-Teller theory (BET), small angle X-ray scattering(SAXS), and molecular adsorption.

In general, the fibers of the disclosure can be formed by any fiberprocess known in the art and are then post-process treated by chemicalmodification, wherein the chemical modification does not includehydrolyzing the polymer.

The disclosure provides a method of treating a fiber including a polymersuch as a polymer comprising at least one of a vinyl acetate moiety or avinyl alcohol moiety, e.g., only at least one vinyl acetate moiety, onlyat least one vinyl alcohol moiety, or both a vinyl acetate moiety and avinyl alcohol moiety, as described herein. In embodiments, the methodincludes contacting a surface of a fiber comprising a polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moiety asdescribed herein with a modification agent to chemically modify at leasta portion of the polymer with the modification agent in a region of thefiber comprising at least a surface of the fiber so as to form amodified fiber. In embodiments, the method includes admixing a fibercomprising a polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety as described herein, a modification agent, andoptionally a solvent for the modification agent to chemically modify atleast a portion of the polymer with the modification agent and form amodified fiber. In embodiments, the fiber is not soluble in the solventfor the modification agent. The degree of modification after contactinga surface of the fiber with a modification agent or after admixing withthe modification agent and a solvent for the modification agent can bedetermined by any suitable method known to one of ordinary skill in theart, such as, attenuated total reflection (ATR), fourier transforminfrared spectroscopy (FTIR), differential scanning calorimetry (DSC),solubility testing (e.g., the example Dissolution and DisintegrationTest Method disclosed herein), titration (e.g., the example TitrationMethod disclosed herein), or the like or combinations thereof. TheTitration Method determines an average degree of hydrolysis or chemicalmodification for a fiber. For a fiber characterized by a constant degreeof hydrolysis or modification across a transverse cross-section of thefiber, the constant degree of hydrolysis or modification is the averagedegree of hydrolysis for the fiber. For a fiber characterized by atransverse cross-section of the fiber having a core-sheath or core-shelltype distribution or a gradient distribution of the degree of hydrolysisor modification, the Titration test provides the average degree ofhydrolysis or modification across all sections of the fiber. As usedherein, and unless specified otherwise, at least a portion of a fiberhas a decreased degree of hydrolysis if any portion of the fiber (e.g.,an exterior surface or portion, a shell surface or portion, and/or aninterior portion) has an increased degree of modification afteradmixing, relative to the degree of hydrolysis of the starting fiber. Itwill be understood that a decrease in degree of hydrolysis to anyportion of the fiber will result in a decrease in the average degree ofhydrolysis of the fiber as determined by the Titration Method. Thus, itwill be understood that the degree of hydrolysis of at least a portionof the polyvinyl alcohol polymer in the fiber will have decreased if theaverage degree of hydrolysis of the fiber, as determined by theTitration Method, is less after admixing the fiber with the modificationagent, relative to the average degree of hydrolysis of the fiber priorto admixing.

As used herein, and unless specified otherwise, at least a portion of afiber has an increased degree of modification if any portion of thefiber (e.g., an exterior surface or portion, a sheath (shell) surface orportion, and/or an interior portion) has an decreased degree ofhydrolysis after contacting or admixing, relative to the degree ofmodification of the starting fiber.

In general, contacting or admixing can include immersing the fibers in amixture of the modification agent and a solvent for the modificationagent. In embodiments, contacting or admixing can include immersing thefibers in a bi-phasic solvent system including the solvent for themodification agent and the modification agent. In embodiments, thebi-phasic solvent system can include water and an organic solvent. Inembodiments, admixing can include stirring the mixture of the fibers,the modification agent, and the solvent for the modification agent. Inembodiments, contacting can include applying an energy source such as acorona treatment, electron beam radiation, or UV radiation, to thefibers.

In embodiments, the method comprises admixing the modification agent andthe fiber under conditions sufficient to provide a controlled amount ofchemical modification (degree of modification) to the polymer and/or acontrolled increase of chemical modification (degree of modification) tothe polymer. In embodiments, the method further comprises admixing asolvent for the modification agent with the modification agent and thefiber. In embodiments, the method comprises admixing the modificationagent, the fiber, and the modification agent solvent under conditionssufficient to provide a controlled amount of chemical modification(degree of modification) to the polymer and/or a controlled increase ofchemical modification (degree of modification) to the polymer. Inembodiments, the method further comprises admixing a solvent for themodification agent with the modification agent and the fiber. Ingeneral, the amount of chemical modification of the treated fiber and/orthe increase of the chemical modification of the treated fiber can bedesigned and controlled by varying the reaction conditions. Reactionconditions that can be modified to provide a controlled amount ofchemical modification and/or increase in chemical modification includethe selection of the modification agent, selection of the solvent forthe modification agent, selection of the concentration of themodification agent in the solvent, reaction (admixing or contacting)time, reaction (admixing or contacting) temperature, and optionalinclusion of an activator.

In general, as the reaction time increases, the chemical modificationwill increase. Thus, the reaction time can be selected to provide adesired increase in the chemical modification of the polymer that makesup the fiber, e.g., polyvinyl alcohol, a copolymer of vinyl acetate andvinyl alcohol, or an anionically modified vinyl alcohol copolymer. Thereaction time can be up to about 48 hours, for example, about 1 minutesto about 36 hours, about 2 minutes to about 24 hours, about 2 minutes toabout 12 hours, about 2 minutes to about 6 hours, about 2 minutes toabout 4 hours, about 2 minutes to about 2 hours, about 2 minutes toabout 1 hour, about 5 minutes to about 1 hour, about 5 minutes to about2 hours, about 5 minutes to about 5 hours, about 5 minutes to about 10hours, about 5 minutes to about 12 hours, about 5 minutes to about 24hours, about 10 minutes to about 24 hours, about 15 minutes to about 24hours, about 30 minutes to about 24 hours, about 1 hour to about 24hours, about 2 hours to about 24 hours, about 3 hours to about 24 hours,about 4 hours to about 24 hours, about 5 hours to about 24 hours, about6 hours to about 24 hours, about 8 hours to about 24 hours, about 10hours to about 24 hours, about 12 hours to about 24 hours, about 12hours to about 18 hours, about 14 hours to about 20 hours, or about 16hours to about 24 hours. In embodiments, the admixing can be for about 1minutes to about 48 hours. In embodiments, the admixing can be for about1 hour to about 36 hours. In embodiments, the admixing can be for about2 hours to about 8 hours.

In general, as the temperature of the reaction is increased, the rate ofchemical modification will increase. Thus, the temperature of thereaction can be selected in combination with reaction time to provide adesired increase in the amount of chemical modification of the polymerthat makes up the fiber, e.g., polyvinyl alcohol, a copolymer of vinylacetate and vinyl alcohol, or an anionically modified vinyl alcoholcopolymer. The temperature of the reaction is not particularly limitedso long as the fiber does not dissolve or decompose and the solvent, ifpresent, remains a liquid under the heating conditions. The reactiontemperature can be from about 10° C. to about 200° C., about 10° C. toabout 190° C., about 10° C. to about 180° C., about 10° C. to about 170°C., about 10° C. to about 160° C., about 10° C. to about 150° C., about10° C. to about 140° C., about 10° C. to about 130° C., about 10° C. toabout 120° C., about 10° C. to about 110° C., about 10° C. to about 100°C., about 10° C. to about 90° C., about 10° C. to about 80° C., about10° C. to about 70° C., about 10° C. to about 60° C., about 10° C. toabout 50° C., about 10° C. to about 40° C., about 10° C. to about 30°C., about 20° C. to about 100° C., about 20° C. to about 90° C., about20° C. to about 80° C., about 30° C. to about 100° C., about 30° C. toabout 90° C., about 30° C. to about 80° C., about 40° C. to about 80°C., about 50° C. to about 80° C., or about 60° C. to about 80° C.Without intending to be bound by theory, it is believed that at highertemperatures as the polarity of the solvent increases the fibers maybegin to swell, gel, and/or dissolve. Accordingly, the temperature ofthe reaction can be selected in combination with the solvent such thatthe fiber will remain insoluble and will not decompose. In embodiments,the method further comprises heating the fiber in a solvent for themodification agent prior to admixing the modification agent with thefiber and solvent. In embodiments, the method further comprises heatinga mixture of the fiber, the modification agent, and the solvent for themodification agent.

The selection of the modification agent can affect the rate of themodification reaction. Thus, the modification agent can be selected incombination with the reaction time and temperature to provide a desiredincrease in the amount of chemical modification of the polymer thatmakes up the fiber, e.g., polyvinyl alcohol, a copolymer of vinylacetate and vinyl alcohol, or an anionically modified vinyl alcoholcopolymer. In embodiments wherein the modification occurs by acid orbase catalyzed transesterification of an ester or amide, the rate of thereaction can be modified based on the nucleophilic strength of themodification agent.

The chemical modification can generally be any desired chemicalmodification of a functional group on the polymer backbone of a fiber toa desired functional group. Non-limiting examples of contemplatedchemical modifications include one or more of an esterification,amidation, amination, carboxylation, nitration, acyloin condensation,allylation, acetylaction, imidization, halogenation, sulfonation,alkylation, acetalyzation, enolyzation, nitrosation, silane coupling,and crosslinking. In embodiments, the methods can comprise admixingunder conditions sufficient to chemically modify the polymer comprisingat least one of a vinyl acetate moiety or vinyl alcohol moiety, e.g.,only at least one vinyl acetate moiety, only at least one vinyl alcoholmoiety, or both a vinyl acetate moiety and a vinyl alcohol moiety,wherein the chemical modification comprises one or more of anesterification, amidation, amination, carboxylation, nitration, acyloincondensation, allylation, acetylaction, imidization, halogenation,sulfonation, alkylation, acetalyzation, enolyzation, nitrosation, andsilane coupling. In embodiments, the methods can comprising contactingunder conditions sufficient to crosslink the polymers, wherein themodification agent comprises a corona treatment, electron beamradiation, or UV radiation. In some embodiments, the polymer afterchemical modification is not crosslinked.

The modification agent can generally be any agent that can chemicallymodify a functional group on the polymer backbone to the desiredfunctional group, and/or catalyze same. Non-limiting examples ofmodification agents include, but are not limited to, an anhydride, acarboxylic acid, an alcohol, an ester, an ether, a sulfonic acid, asulfonate, a click chemistry reagent, an amide, an amine, a lactam, anitrile, a ketone, an allyl compound, an acetyl compound, a halogencompound, an alkyl containing compound, an imide, an acetal containingcompound, an enolate, a nitro containing compound, a silane, anaziridine, an isocyanate, or any combination thereof. In embodiments,the modification agent comprises an anhydride, a carboxylic acid, analcohol, an ester, an ether, a sulfonic acid, a sulfonate, a clickchemistry reagent, an amide, an amine, a nitrile, a ketone, an allylcompound, an acetyl containing compound, a halogen containing compound,an alkyl containing compound, an imide, an acetal containing compound,an enolate, a nitro containing compound, a silane, an aziridine, anisocyanate, an energy source, or any combination thereof. Inembodiments, the modification agent comprises an anhydride, an amine, asulfonate, a sulfonic acid, a monocarboxylic acid, a dicarboxylic acid,or any combination thereof. In embodiments, the modification agentcomprises a sulfonate. In embodiments, the sulfonate comprisesaminopropyl sulfonate. In embodiments, the modification comprises anamine or lactam. In embodiments, the lactam comprises a pyrrolidone or acaprolactam. In embodiments, the modification agent comprises a sulfonicacid. In embodiments, the sulfonic acid comprises2-acrylamido-2-methylpropanesulfonic acid (AMPS). In embodiments, themodification agent comprises a monocarboxylic acid or dicarboxylic acid.In embodiments, the monocarboxylic acid or dicarboxylic acid comprisesacetic acid, maleic acid, monoalkyl maleate, dialkyl maleate, fumaricacid, monoalkyl fumarate, dialkyl fumarate, itaconic acid, monoalkylitaconate, dialkyl itaconate, citraconic acid, monoalkyl citraconate,dialkyl citraconate, mesaconic acid, monoalkyl mesaconate, dialkylmesaconate, glutaconic acid, monoalkyl glutaconate, dialkyl glutaconate,alkyl (alkyl)acrylates, alkali metal salts of the foregoing, hydrolyzedalkali metal salts thereof, esters thereof, or combinations thereof. Inembodiments, the modification agent comprises an anhydride. Inembodiments, the anhydride is an organic acid anhydride and the organicacid anhydride comprises acetic anhydride, propionic anhydride,isobutyric anhydride, maleic anhydride, phthalic anhydride, glutaricanhydride, itaconic anhydride, citraconic anhydride, glutaconicanhydride, or any combination thereof. In embodiments, the organic acidanhydride comprises maleic anhydride. In embodiments, the modificationagent comprises an aziridine. In embodiments, the aziridine is anoligomer. In embodiments, the modification agent comprises anisocyanate. In embodiments, the isocyanate is an oligomer. In someembodiments, the starting fiber comprises a copolymer of vinyl acetateand vinyl alcohol, and the modification agent comprises an organic acidanhydride. The hydroxyl group (—OH) from the vinyl alcohol moietiesreacts with the modification agent and chemically bonds and attaches themodification moiety onto the polymer chain. In certain instances, thedegree of modification is the same as (equal to) the degree ofhydrolysis of the polymer before modification when the hydroxyl group isfully reacted.

As used herein, the term “click chemistry reagent” refers to a reagentthat can chemically modify a polymer backbone of a fiber to a firstfunctional group of a click chemistry reactive pair. As used herein, theterm “click chemistry reactive pair” refers to a pair of complementaryfunctional groups that is capable of undergoing a “click chemistry”reaction. As used herein, “first functional group of a click chemistryreactive pair” refers to one of the pair of complementary functionalgroups that is capable of undergoing a “click chemistry” reaction. Ingeneral, there are four main classes of click chemistry reactions: 1)cycloadditions, 2) nucleophilic ring-openings, 3) carbonyl chemistry ofthe non-aldol type, and 4) additions to carbon-carbon multiple bonds.The click chemistry reactive pair can be a pair of complementaryfunctional groups that are compatible with the four classes of clickchemistry reactions shown above, such as thiol/alkene, azide/alkynes,azide/alkene, alkene/tetrazine, isonitrile/tetrazine, etc. Furtherexamples of click chemistry reactive pairs can be found in Wang et. al.,Pharm Res., 2008, 25(10): 2216-2230; Bowman et al., Adv. Funct. Mater.,2014, 24, 2572-2590; and Jozwiak et al., Chem. Rev., 2013, 113,4905-4979.

In general, as the concentration of modification agent in the solventfor the modification agent increases, the rate of reaction willincrease. Thus, the concentration of the modification agent can beselected in combination with the reaction time, reaction temperature,and selection of the modification agent to provide a desired increase inthe degree of modification of the polymer that makes up the fiber, e.g.,polyvinyl alcohol, a polyvinyl alcohol copolymer, or a modifiedpolyvinyl alcohol copolymer. In general, the concentration of themodification agent in the solvent for the modification agent can be anyconcentration. Typically, the concentration will be selected such thatall of the modification agent provided is in solution. In embodiments,the modification agent can be provided in an amount of about 0.2% toabout 75% (w/w) based on the weight of the solvent, for example, about0.2% to about 75%, about 0.2% to about 50%, about 0.2% to about 25%,about 0.5% to about 20%, about 1% to about 18%, about 2% to about 16%,about 5% to about 15%, about 8% to about 12%, or about 10%. Inembodiments, the modification agent is provided in an amount of about0.2% to about 25% (w/w), based on the weight of the solvent. Inembodiments, the modification agent is provided in an amount of about 2%to about 25% (w/w), based on the weight of the solvent. In embodiments,the modification agent is provided in an amount of about 5% to about 15%(w/w), based on the weight of the solvent. In embodiments wherein themodification agent is an energy source, in general, as the intensity ofthe energy source increases, the rate of reaction will increase. Thus,the energy intensity can be selected in combination with reaction time,reaction temperature, and selection of the modification agent to providea desired increase in the degree of modification of the polymer thatmakes up the fiber, e.g., polyvinyl alcohol.

The solvent for the modification agent can generally be any solvent inwhich the modification agent is soluble and the fiber to be treated isinsoluble at the temperature at which the treatment takes place for theduration of contact of the fiber with the solvent. In embodiments, thefiber is insoluble in the solvent prior to treatment. In embodiments,the fiber is insoluble in the solvent during treatment. In embodiments,the fiber is insoluble in the solvent after treatment. In general, thesolvent can be selected in combination with the reaction time, reactiontemperature, selection of the modification agent and concentrationthereof to provide a desired increase in the degree of modification ofthe polymer that makes up the fiber, e.g., polyvinyl alcohol. As thepolarity of the solvent increases, the diffusion of the solvent into thepolymer matrix of the fiber generally increases, resulting in anincrease in the diffusion of the modification agent into the polymermatrix. Without intending to be bound by theory, it is believed that asthe polarity of the solvent increases, the degree of modification of theinner/core section of the fiber can increase, such that the degree ofmodification can be increased across a transverse cross-section of thefiber. Further, without intending to be bound by theory, as the polarityof the solvent decrease, the diffusion of the solvent into the polymermatrix of the fiber generally decreases, such that the degree ofmodification can be increased at a portion of thesurface/exterior/sheath of the fiber. Modification of the polymer of thefiber at a portion of the surface/exterior/or sheath of the fiber alsoresults in an average increase in the degree of modification across atransverse cross-section of the fiber. Further, without intending to bebound by theory, a combination of solvents can be used to provide adiffusion controlled radiant gradient of the degree of modification ofthe polymers of the treated fiber. In embodiments, the combination ofsolvents can be a bi-phasic solvent system. In embodiments, thebi-phasic solvent system can comprise water and an organic solvent. Inembodiments, the bi-phasic solvent system can comprise water and analcohol (e.g., methanol, ethanol, isopropanol, butanol, pentanol). Inembodiments, the bi-phasic solvent system comprises water and methanol.

In embodiments, the solvent for the modification agent solution can becharacterized by the Hansen Solubility Parameter (HSP). Withoutintending to be bound by theory, it is believed that the three HSPvalues, dispersion, molar volume, and hydrogen-bonding, are indicatorsof miscibility and, thus, solvation or swelling of polyvinyl alcohol bya particular solvent. Further, without intending to be bound by theory,it is believed that while hydrogen bonding is the largest predictor ofexpected behavior, the summation of all the parameters, H_(total), isalso predictive. In general, when the HSP values of the solvent are lessthan the HSP values of the polyvinyl alcohol, the more dissimilar theHSP values are between the solvent and the polyvinyl alcohol, the lowerthe diffusivity of the solvent into the polyvinyl alcohol. Withoutintending to be bound by theory, it is believed that when the H_(total)value of the solvent is about 4 to about 15 units lower than theH_(total) value of the polyvinyl alcohol, the rate of solvent uptake anddiffusivity of the solvent into the polyvinyl alcohol is such that agradient of solvent uptake and, thus, modification agent uptake, willoccur, providing a gradient in the degree of modification of thepolyvinyl alcohol fiber across a transverse cross section with a higherdegree of modification at a surface region, relative to an inner, coreregion. Without intending to be bound by theory, it is believed thatwhen the H_(total) value of the solvent is about 4 to about 15 unitshigher than the H_(total) value of the polyvinyl alcohol, the rate ofsolvent uptake and diffusivity of the solvent into the polyvinyl alcoholis such that solvent uptake and, thus, modification agent uptake, willoccur quickly providing a uniform degree of modification across atransverse cross-section of the polyvinyl alcohol fiber. Further,without intending to be bound by theory, it is believed that when theH_(total) value of the solvent is more than 15 units lower than that ofthe polyvinyl alcohol of the fiber the diffusivity will be limited suchthat only an outer surface of the fiber will be treated with themodification agent and when the H_(total) value of the solvent is morethan 15 units higher than that of the polyvinyl alcohol of the fiber,the solvent will dissolve the polyvinyl alcohol of the fiber.

In embodiments, the solvent for the modification agent comprises a polarsolvent. In embodiments, the solvent comprises octanol, heptanol,hexanol, pentanol, butanol, propanol, tetrahydrofuran, dichloromethane,acetone, ethanol, N-methylpyrrolidone, methanol, acetonitrile, ethyleneglycol, N,N-dimethylformamide, glycerol, dimethyl sulfoxide, formicacid, water, or any combination thereof. In embodiments, the solventcomprises n-octanol, n-heptanol, n-hexanol, n-pentanol, n-butanol,isobutanol, sec-butanol, tert-butanol, n-propanol, isopropanol, acetone,ethanol, N-methylpyrrolidone, methanol, acetonitrile,N,N-dimethylformamide, dimethyl sulfoxide, formic acid, water, or anycombination thereof. In embodiments, the solvent comprises n-propanol,acetone, ethanol, N-methylpyrrolidone, methanol, acetonitrile,N,N-dimethylformamide, dimethyl sulfoxide, formic acid, water, or anycombination thereof. In embodiments, the solvent comprises one or moresolvents selected from the group consisting of methanol, ethanol,n-propanol, isopropanol, acetone, N-methylpyrrolidone, acetonitrile,N,N-dimethylformamide, dimethyl sulfoxide, formic acid, water, and anycombination thereof. In embodiments, the solvent comprises an alcoholthat is a liquid under the admixing conditions. In embodiments, thesolvent comprises methanol. In embodiments, the solvent comprisesmethanol and at least one additional solvent. In embodiments, thesolvent comprises methanol and water. In embodiments, the solventcomprises at least one of butanol, pentanol, hexanol, heptanol, andoctanol in combination with water. In embodiments, the solvent comprisesa mixture of a first solvent and a second solvent. In embodiments, thefirst solvent comprises water and the second solvent comprises analcohol. In embodiments, the second solvent comprises methanol, ethanol,n-propanol, isopropanol, or any combination thereof. In embodiments, thesolvent comprises DMSO and water. In embodiments, the solvent comprisesDMSO and water and the DMSO and water are provided in a weight ratio ofabout 40/60 to 80/20. Without intending to be bound by theory, it isbelieved that as the amount of water increases above 60% or the amountof DMSO increases above about 80%, the interaction of the respectivesolvents with polyvinyl alcohol increases, resulting in increasedswelling and gelling of the polymer.

In embodiments, the solvent comprises a nonpolar solvent. Inembodiments, the solvent comprises hexanes, cyclohexane, methylpentane,pentane, cyclopropane, dioxane, benzene, pyridine, xylene, toluene,diethyl ether, chloroform, or any combination thereof.

In embodiments, the solvent comprises a mixture of a first solvent and asecond solvent. In embodiments, the first solvent comprises a polarsolvent and the second solvent comprises a nonpolar solvent. Inembodiments, the first solvent has a first dielectric constant and thesecond solvent has a second dielectric constant and the dielectricconstant of the first solvent is higher than the dielectric constant ofthe second solvent. In embodiments, the first dielectric constant is 5or less, 4 or less, 3 or less, or 2 or less. In embodiments, the seconddielectric constant is greater than 5, greater than 7.5, greater than10, greater than 15, greater than 18, greater than 20, greater than 25,or greater than 30. In embodiments, the difference between the firstdielectric constant and the second dielectric constant is at least 3, atleast 5, at least 8, or at least 10. In embodiments, wherein the solventcomprises a mixture of a first solvent and a second solvent, the firstsolvent and the second solvent can be provided in any ratio providedthat the hydrolysis agent is soluble in the mixture and the fiber is notsoluble in the mixture prior to treatment, during treatment, and aftertreatment. In embodiments, the first solvent and second solvent can beprovided in a weight ratio of about 99/1 to about 1/99, about 95/5 toabout 5/95, about 90/10 to 10/90, about 85/15 to about 15/85, about80/20 to about 20/80, about 75/25 to about 25/75, about 70/30 to about30/70, about 65/35 to about 35/65, about 60/40 to about 40/60, about55/45 to about 45/55, or about 50/50.

In embodiments, the methods of the disclosure further include admixingthe fiber, the modification agent, and the optional solvent with anactivator. The activator can generally be any additive that facilitatesthe treatment of the fiber by the modification agent. The activator cangenerally include a catalyst for reducing the activation energy of thereaction between the polymer of the fiber and the modification agent ora compound that facilitates diffusion of the modification agent into thepolymer matrix, for example. In embodiments, the activator can comprisean acid, a base, an aziridine, a free radical initiator, or acombination thereof. In embodiments, the activator is a free radicalinitiator. In embodiments, the free radical initiator can comprise aperoxide. In embodiments, the peroxide can comprise benzoic peroxide,hydrogen peroxide, dibenzoyl peroxide (BPO), didodecanoyl (dilauroyl)peroxide (LPO), or a combination thereof. In embodiments, the freeradical initiator can comprise an azo compound, such as,2,2′-Azobisisobutyronitrile (AIBN). In embodiments, the activator is anacid. In embodiments, the acid can comprise an organic acid, inorganicacid, or a combination thereof. In embodiments, the organic acid cancomprise carboxylic acids such as formic acid, acetic acid, oxalic acid,malonic acid, or a combination thereof. In embodiments, the inorganicacid can comprise boric acid, nitric acid, nitrous acid, phosphoricacid, phosphorous acid, sulfuric acid, hydrosulfuric acid, chloric acid,chlorous acid, hypochlorous acid, a hydrohalic acid, or a combinationthereof. In embodiments, the hydrohalic acid can comprise hydrofluoricacid, hydrochloric acid, hydrobromic acid, hydroiodic acid, or acombination thereof. In embodiments, the activator is a base. Inembodiments, the base can comprise a metallic hydroxide. In embodiments,the metallic hydroxide can comprise lithium hydroxide, sodium hydroxide,potassium hydroxide, rubidium hydroxide, caesium hydroxide, or acombination thereof.

The modified fiber can generally be a fiber that includes a chemicalmodification after admixing with the modification agent. Non-limitingexamples of chemical modifications that the modified fiber can comprise,includes a monocarboxylic acid, a dicarboxylic acid, a sulfonic acid, asulfonate, a first functional group of a click chemistry reactive pair,an amide, an amine, a carbamate, a nitrile, a ketone, an ester, anallyl, an acetyl, a halogen, an alkyl, an imide, an acetal, an enolate,a nitro, a silane, a crosslink, or any combination thereof. Inembodiments, the modified fiber comprises a monocarboxylic acid, adicarboxylic acid, a sulfonic acid, a sulfonate, a first functionalgroup of a click chemistry reactive pair, an amide, an amine, a nitrile,a ketone, an ester, an allyl, an acetyl, a halogen, an alkyl, an imide,an acetal, an enolate, a nitro, a silane or a combination thereof. Inembodiments, the modified fiber comprises a sulfonate, a sulfonic acid,or both. In embodiments, the modified fiber comprises vinyl sulfonicacid, allyl sulfonic acid, ethylene sulfonic acid,2-acrylamido-1-methylpropanesulfonic acid,2-acrylamido-2-methylpropanesufonic acid,2-methacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate,alkali metal salt derivatives of the foregoing, or combinations thereof.In embodiments, the modified fiber comprises a sulfonate. Inembodiments, the sulfonate comprises aminopropyl sulfonate. Inembodiments, the modified fiber comprises a sulfonic acid. Inembodiments, the sulfonic acid comprises2-acrylamido-2-methylpropanesulfonic acid (AMPS) and/or the sodium saltof AMPS. In embodiments, the modified fiber comprises an amine or acarbamate as a moiety from a lactam. In embodiments, such a carbamatecan be from a lactam comprising a pyrrolidone or a caprolactam. Inembodiments, the modified fiber comprises a monocarboxylic acid ordicarboxylic acid. In embodiments, the monocarboxylic acid ordicarboxylic acid comprise acetic acid, maleic acid, monoalkyl maleate,dialkyl maleate, fumaric acid, monoalkyl fumarate, dialkyl fumarate,itaconic acid, monoalkyl itaconate, dialkyl itaconate, citraconic acid,monoalkyl citraconate, dialkyl citraconate, mesaconic acid, monoalkylmesaconate, dialkyl mesaconate, glutaconic acid, monoalkyl glutaconate,dialkyl glutaconate, alkyl (alkyl)acrylates, alkali metal salts of theforegoing, hydrolyzed alkali metal salts thereof, esters thereof, orcombinations thereof. In embodiments, the dicarboxylic acid comprises amonomethyl maleate. In embodiments, the modified fiber comprises a firstfunctional group of a click chemistry reactive pair as disclosed above.In embodiments, the modified fiber comprises a first functional group ofa click chemistry reactive pair and an active agent as disclosed hereincomprises a second functional group of the click chemistry reactivepair. Thus, a modification agent can be contemplated to modify a fiberwith a particular first functional group of a click chemistry reactivepair, such that the desired active agent comprising the secondfunctional group of the click chemistry reactive pair can be readilyreacted with the modified fiber to form a fiber bonded to the desiredactive agent. In embodiments, the modified fiber comprises an amide. Inembodiments, the modified fiber comprises an ester. In embodiments, themodified fiber comprises an amine.

In general, an increase in the amount of chemical modification (degreeof modification) of the modified fiber, relative to the fiber prior tothe post-processing methods disclosed herein, can be in a range of 0.1mol % to about 50 mol %. For example, the degree of modification fromthe methods disclosed herein can be about 1 mol %, about 2 mol %, about3 mol %, about 4 mol %, about 5 mol %, about 6 mol %, about 7 mol %,about 8 mol %, about 9 mol %, about 10 mol %, about 11 mol %, about 12mol %, about 13 mol %, about 14 mol %, about 15 mol %, about 20 mol %,about 30 mol %, about 40 mol % or about 50 mol %, such as, in a range of1 mol % to 15 mol %, about 1 mol % to about 10 mol %, about 1 mol % toabout 8 mol %, about 2 mol % to about 8 mol %, about 2 mol % to about 8mol %, about 3 mol % to about 8 mol %, about 3 mol % to about 6 mol %,or about 1 mol % to about 4 mol %.

The reaction conditions can also be selected to design and control thesolubility mechanism and/or absorption capacity and retention of thetreated fiber. For example, the reaction conditions can be selected toprovide a fiber having a transverse cross-section characterized by: (a)a core-sheath structure, wherein the polymer of the sheath has adifferent, e.g., greater, degree of modification than the polymer of thecore (FIG. 2A), (b) a radial gradient in the degree of modification ofthe polymer, for example, in an order of increasing degree ofmodification, from an interior region to a surface region (FIG. 2B; FIG.3), or (c) a consistent degree of modification across the transversecross-section (FIG. 2C). The resulting fibers can have differentsolubility mechanisms (for example, immediate release, delayed release,or triggered release), chemical compatability/resistance, and/orabsorption capacity and retention properties. Reaction conditions thatcan be modified to provide a controlled fiber structure include theselection of the modification agent, selection of the concentration ofthe modification agent in the solvent for the modification agent,reaction (contacting or admixing) time, reaction (contacting oradmixing) temperature, selection of solvent for the modification agent,and optional inclusion of an activator.

A fiber having a core-sheath structure or core-shell structure can beprepared by treating a fiber having a polymer such as polyvinyl alcoholwith a modification agent and a solvent under conditions sufficient tominimize the radial diffusion of the solvent and the modification agentinto an inner core region of the fiber. Diffusion of the solvent andmodification agent into an inner core region of the fiber can beminimized, for example, by selecting a short reaction time, a lowreaction temperature, and/or including a nonpolar solvent. Inembodiments, the contacting of the methods of the disclosure isperformed under conditions sufficient to provide a fiber comprising apolymer having vinyl alcohol moieties having a transverse cross-sectioncharacterized by a core-sheath structure, wherein the polymer of thesheath has a greater degree of modification than the polymer of thecore. In embodiments, the conditions sufficient to provide a fiberhaving a transverse cross-section characterized by a core-sheathstructure, wherein the polymer of the sheath has a greater degree ofmodification than the polymer of the core comprises including a solventhaving a dielectric constant of 20 or less, 18 or less, 14 or less, or10 or less. In embodiments, the conditions sufficient to provide a fiberhaving a transverse cross-section characterized by a core-sheathstructure, wherein the polymer of the sheath has a greater degree ofmodification than the of the core comprises admixing the fiber and themodification agent solution at a temperature in a range of about 10° C.to about 30° C., about 10° C. to about 25° C., or about 15° C. to about25° C. In embodiments, the conditions sufficient to provide a fiberhaving a transverse cross-section characterized by a core-sheathstructure, wherein the polymer of the sheath has a greater degree ofmodification than the polymer of the core comprises admixing the fiberand the modification agent for a time of about 2 minutes to about 6hours, about 2 minutes to about 4 hours, about 5 minutes to about 3hours, about 10 minutes to about 2 hours, or about 15 minutes to about 1hour. In embodiments, the conditions sufficient to provide a fiberhaving a transverse cross-section characterized by a core-sheathstructure, wherein the polymer of the sheath has a greater degree ofmodification than the polymer of the core comprises including a solventhaving a dielectric constant of 20 or less, 18 or less, 14 or less, or10 or less, admixing the fiber, the modification agent, and the solventat a temperature in a range of about 10° C. to about 30° C., about 10°C. to about 25° C., or about 15° C. to about 25° C., and admixing thefiber, the modification agent, and the solvent for a time of about 2minutes to about 6 hours, about 2 minutes to about 4 hours, about 5minutes to about 3 hours, about 10 minutes to about 2 hours, or about 15minutes to about 1 hour. Such fibers having a transverse cross-sectioncharacterized by a core-sheath structure wherein the polymer of thesheath has a greater degree of modification than the polymer of the corecan provide delayed release properties of an active agent provided inthe interior of the fiber, controlled release properties of an activeagent conjugated to the modified polymer, triggered release of an activeagent provided in the interior of the fiber and/or conjugated to themodified polymer, and/or enhanced chemical resistance relative to afiber having no modification. In embodiments, the modified sheath regioncan be substantially continuous. As used herein and unless specifiedotherwise, “substantially continuous” refers to a homogeneousdistribution of modifications across the surface area of the fiber suchthat at least about 60% of the surface area of the fiber comprises amodification. In embodiments, at least about 75%, at least about 80%, atleast about 90%, or at least about 95% of the surface area of the fibercomprises a modification. Without intending to be bound by theory, it isbelieved that when the modified sheath region is substantiallycontinuous, the fiber can demonstrate enhanced chemical resistance whenin contact with harsh chemicals such as oxidizing agents, such that thefiber is protected from discoloration and reduced solubility. Further,without intending to be bound by theory, it is believed that areas ofdiscontinuation of the modified sheath region are areas susceptible toharsh chemical that allow infiltration of the harsh chemical anddeterioration of the fiber by the harsh chemical over time, when thefiber is in contact with the harsh chemical.

As used herein and unless specified otherwise, “delayed release” of anactive agent from a fiber means that the entirety of the active agent isnot immediately released from the fiber when contacted with a solvent(usually water) under the conditions of an end use application of thefiber. For example, a fiber containing an active agent and used in alaundry application may not immediately release the entirety of theactive under wash conditions. Rather, the active can diffuse from thefiber over time. As used herein and unless specified otherwise,“triggered release” of an active agent from a fiber means that none ofthe active is released from the fiber until a trigger condition is met.For example, a fiber containing an active agent and used in a laundryapplication may not release the active agent until the wash waterreaches a predetermined temperature and/or pH.

Trigger conditions can include, but are not limited to, temperature, pH,UV/VIS radiation, IR radiation, presence of ions, presence of catalysts,or a combination thereof.

As the thickness of the sheath structure increases, the stability of afiber having a core swollen and saturated with a fluid increases but theamount of polymer available in the core for absorbing a fluid decreases.The thickness of the sheath can be controlled by controlling thediffusion of the modification agent into the polymer structure of thefiber. It will be understood that because treatment of the innerportions of the fiber is diffusion controlled, the sheath may have avariation in thickness around a perimeter of the fiber and the innerportion of the sheath may have a degree of modification that is lessthan the degree of modification of the polymer at the exterior surfaceof the sheath but greater than the degree of modification of the polymerat the center of the fiber. Thus in some embodiments, the transversecross-section of the fiber can be characterized by a core-sheathstructure and can also be characterized as having an increasing gradientfrom an inner portion of the fiber to an exterior portion of the fiber.

A fiber having a transverse cross-section characterized by an increasingradial gradient structure can be prepared by treating a fiber having apolymer such as polyvinyl alcohol or copolymer of vinyl acetate andvinyl alcohol having no degree of modification with a modification agentand a solvent under conditions sufficient to modify the radial diffusionof the solvent and the modification agent into an inner region of thefiber. In embodiments, a fiber having a transverse cross-sectioncharacterized by an increasing radial gradient structure from an innerregion to an exterior region can be prepared using multiple solventshaving different rates of diffusion (concurrently or step-wise),changing the temperature during admixing to modify the rate of diffusionof the solvent and modification agent into the fiber, and/or selectingthe reaction time such that it is long enough to allow some modificationagent diffuses into the inner region to modify the degree ofmodification of the polymer but is not so long as to allow the polymerof the inner portion to be chemically modified to the same extent as thepolymer of the exterior/surface portion. In embodiments, the admixing ofthe methods of the disclosure is performed under conditions sufficientto provide a fiber having a transverse cross-section characterized by anincreasing gradient in the degree of modification of the polymer from aninterior region of the fiber to a surface region of the fiber. Suchfibers having a transverse cross-section characterized by an increasinggradient of degree of modification can provide delayed releaseproperties of an active agent provided in the interior of the fiber,triggered release of an active agent provided in the interior of thefiber, increased absorbance relative to a fiber having a consistentdegree of modification across a transverse cross-section, and/orimproved retention of absorbed fluids.

Fibers having a transverse cross-section characterized by a core-sheathstructure and/or an increasing radial structure can have active agentsloaded in the core/inner regions. Actives can be loaded to thecore/inner regions by contacting a fiber with a solution of an activeagent and allowing the active agent solution to diffuse into the polymerstructure, resulting in the core/inner regions of the fiber to absorbthe active agent solution and swell. The active agent can be any activeagent disclosed herein that is soluble in the active agent solutionsolvent. The solvent can be any solvent disclosed herein. Withoutintending to be bound by theory, it is believed that as the polarity ofthe solvent increases, the rate of diffusion to the core/inner regionsof the fiber increases. An exemplary solvent is water provided that thewater of the active agent solution is maintained at a temperature belowthe solubility temperature of the polymer that makes up the core/innerregion of the fiber and the sheath/exterior region of the fiber.

A fiber having a transverse cross-section characterized by the polymerhaving the same degree of modification across (throughout) thetransverse cross-section can be prepared by treating a fiber having apolymer such as polyvinyl alcohol or a polyvinyl alcohol copolymer witha modification agent and a solvent under conditions sufficient tomaximize the radial diffusion of the solvent and the modification agentinto an inner core region of the fiber. Diffusion of the solvent andmodification agent into an inner core region of the fiber can bemaximized, for example, by selecting a long reaction time, a highreaction temperature, and/or including a highly polar solvent. Inembodiments, the admixing of the methods of the disclosure is performedunder conditions sufficient to provide a fiber having a transversecross-section characterized by the polymer having the same degree ofmodification across the transverse cross-section.

Advantageously, in some embodiments, without intending to be bound bytheory, as the degree of modification of the polymer at the surfaceregion of a fiber increases, relative to the degree of modification (ifany) of the polymer in the inner region of the fiber, the bulksolubility of the fiber can increase or be maintain at the same level,allowing for more precise tuning of the solubility parameters of thefibers and different solubility characteristics of the fibers, relativeto merely selecting a fiber having a consistent degree of modificationor no degree of modification throughout the fiber.

The disclosure further provides a method of treating a fiber comprisingcontacting a surface of a fiber comprising a polymer comprising at leastone of a vinyl acetate moiety or a vinyl alcohol moiety, e.g., only atleast one vinyl acetate moiety, only at least one vinyl alcohol moiety,or both a vinyl acetate moiety and a vinyl alcohol moiety, with amodification agent and a solvent for the modification agent tochemically modify at least a portion of the polymer with themodification agent in a region of the fiber comprising at least thesurface of the fiber. In embodiments, the contacting can be performed byimmersion, spraying, transfer coating, wicking, foaming, brushing,rolling, humidification, vapor deposition, printing, or a combinationthereof. In embodiments, the polymer is selected from the groupconsisting of a polyvinyl alcohol homopolymer, a polyvinyl alcoholcopolymer, a modified polyvinyl alcohol copolymer, or a combinationthereof. The modification agent can include any modification agentdisclosed herein and the solvent for the modification agent can includeany solvent disclosed herein. In embodiments, the method can furthercomprise contacting the surface of the fiber with the modification agentafter formation of the fiber as part of a continuous inline process. Forexample, the fiber can be formed from a polymer mixture at a firststation and then transferred to a second station where the surface ofthe fibers can be treated. In another example, the fiber can be treatedon an apparatus including a fiber supply station, a fiber treatingstation, and a fiber collection station. In embodiments, the fiber is inmotion during the contacting of the surface of the fibers. Inembodiments, the contacting the surface of the fiber with themodification agent and a solvent is performed in a batch-by-batchprocess or a continuous in-line process. For example, the fibers can beprepared in bulk and can be treated with the modification agent prior toformation of the fibers into nonwoven webs. In embodiments, the fibercomprises staple fiber, staple yarn, fiber fill, needle punch fabrics,bonding fibers, or a combination thereof. In embodiments, the fibercomprises staple fiber. In embodiments, the method further compriseswashing and drying the fiber after contacting the surface of the fiberwith the modification agent. The washing can be by rinsing the fiberwith a non-solvent. A non-solvent refers to a liquid that does notsolubilize the fibers, but remove unreactive chemicals such as themodification agent. Examples of a non-solvent includes either polar oraprotic solvents. For example, acetone can be used. The drying the fibercan be by air jet drying, agitating, vortexing, or centrifuging.

In embodiments, the methods disclosed herein of treating a fibercomprising the polymer comprising a polyvinyl alcohol copolymer having adegree of hydrolysis in a range of from about 79% to about 99.9%, e.g.,a degree of hydrolysis of 88%, 92%, or 96%, the modification agentcomprises maleic anhydride, and the solvent comprises methanol, and themethod further comprises admixing an activator comprising sodiumhydroxide with the fiber, modification agent, and solvent. Inembodiments, the methods disclosed herein of treating a fiber comprisingthe fiber comprises a polyvinyl alcohol copolymer having a degree ofhydrolysis of 88%, 92%, or 96%, the modification agent comprises maleicanhydride, and the solvent comprises methanol, and admixing comprisescombining the fiber and the solvent and heating the mixture to about 65°C. to about 75° C. to form a heated mixture; adding to the heatedmixture the maleic anhydride and an activator comprising sodiumhydroxide to form a reaction mixture; and stirring the reaction mixtureat about 65° C. to about 75° C., for about 3 to 7 hours.

The disclosure provides a fiber treated according to the methods of thedisclosure.

The disclosure provides a fiber having a surface region and an interiorregion. The fiber comprises a polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety, e.g., only at least one vinylacetate moiety, only at least one vinyl alcohol moiety, or both a vinylacetate moiety and a vinyl alcohol moiety, chemically modified with amodification agent as described herein. The polymer in the fiber ischemically modified with the modification agent, for example, chemicallybonded with the modification agent moiety through a reaction with thehydroxyl group in the vinyl alcohol moiety. In embodiments, the fiberhas a transverse cross-section including an interior region having afirst degree of modification and a surface region having a second degreeof modification different from, e.g., greater than, the first degree ofmodification of the polymer in the interior region. The first degree ofmodification may be zero or greater than zero. When the first degree ofmodification is zero, the interior region of the fiber comprises thepolymer including at least one a vinyl acetate moiety or a vinyl alcoholmoiety, e.g., only at least one vinyl acetate moiety, only at least onevinyl alcohol moiety, or both a vinyl acetate moiety and a vinyl alcoholmoiety, without modification, for example, polyvinyl alcohol, apolyvinyl alcohol copolymer, an anionically modified polyvinyl alcoholcopolymer, or a combination thereof. In embodiments, the disclosureprovides a fiber having a surface region and an interior region. Inembodiments, the fiber comprises a polymer comprising vinyl acetatemoieties and vinyl alcohol moieties modified with a modification agent.The fiber has a transverse cross-section including the interior regionhaving the first degree of modification and the surface region having asecond degree of modification greater than the first degree ofmodification.

The fiber of the disclosure can have a transverse cross-section of thefiber having an increasing gradient in the degree of modification of thepolymer from the interior region to the surface region. In embodiments,the fiber of the disclosure can have a transverse cross-section of thefiber having the same degree of modification of the polymer from theinterior region to the surface region. In some embodiments, the polymerbefore modification comprises polyvinyl alcohol, a copolymer of vinylacetate and vinyl alcohol, an anionically modified polyvinyl alcoholcopolymer, or a combination thereof. After the modification, the polymeris chemically bonded with the modification agent moieties throughreaction between the hydroxyl groups in the vinyl alcohol and themodification agent.

As shown in FIG. 3, the disclosure provides a fiber comprising atransverse cross-section having a core-sheath structure or a core-shellstructure. The fiber comprises a first region, e.g., a core region(denoted 401 in FIG. 3), comprising a polymer comprising at least one ofa vinyl acetate moiety or a vinyl alcohol moiety, e.g., only at leastone vinyl acetate moiety, only at least one vinyl alcohol moiety, orboth a vinyl acetate moiety and a vinyl alcohol moiety. Such a polymerin the core region has no modification or has a first degree ofmodification with a modification agent. The first degree of modificationcan be zero or greater than zero. The fiber also comprises a secondregion, e.g., a sheath region (denoted 402 in FIG. 3), comprising such apolymer modified with the modification agent and having a second degreeof modification, greater than the first degree of modification for thepolymer of the first region. In embodiments, the fiber can comprise atransverse cross-section having a core-sheath structure. The fibercomprises a first region, e.g., a core region, comprising polyvinylalcohol or a polyvinyl alcohol copolymer, and a second region, e.g., asheath region, comprising such a polymer modified with a second degreeof modification different than the first degree of modification in thefirst region. In embodiments, the fiber can comprise a transversecross-section having a core-sheath structure. The fiber comprises afirst region, e.g., a core region, comprising polyvinyl alcohol or apolyvinyl alcohol copolymer, and a second region, e.g., a sheath region,comprising such a polymer having a second degree of modification greaterthan the first degree of modification of the polymer in the firstregion. In some embodiments, the polyvinyl alcohol copolymer is acopolymer of vinyl acetate and vinyl alcohol before modification. Thepolymer in the fiber is chemically modified with the modification agent,for example, chemically bonded with the modification agent moietythrough a reaction with the hydroxyl group in the vinyl alcohol moiety.In embodiments, the fiber further comprises at least one third region,e.g., at least one intermediate region (denoted 403 in FIG. 3), disposedbetween the first region and the second region and comprising thepolymer having a third degree of modification intermediate between thefirst degree of modification of the polymer of the first region and thesecond degree of modification of the polymer of the second region. Inembodiments, the fiber further comprises at least one third region,e.g., at least one intermediate region (denoted 403 in FIG. 3), disposedbetween the first region and the second region and comprising a polymerhaving a third degree of modification greater than the first degree ofmodification in the first region and less than the second degree ofmodification in the second region. In embodiments, the fiber cancomprise a plurality of third regions, e.g., a plurality of intermediateregions (denoted 403 a, 403 b in FIG. 3), disposed between the firstregion and the second region. The transverse cross-section of the fiberhas an increasing gradient in the degree of modification of the polymerfrom the first region to the second region. In embodiments, theplurality of third regions includes a polymer modified from polyvinylalcohol or a polyvinyl alcohol copolymer with a modification agent. Thetransverse cross-section of the fiber has an increasing gradient in thedegree of modification of the polymer from the first region to thesecond region.

In embodiments, the fibers of the disclosure can have a difference inthe degree of modification of the polymers in the first and secondregions of about 0.1%, about 0.3%, about 0.5%, about 0.7%, about 1%,about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%,about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, orabout 15%, for example, in a range of 0.1% to 15%, about 0.3% to about10%, about 0.5% to about 8%, about 1% to about 8%, about 2% to about 5%,about 1% to about 4%, or about 0.5% to about 5%. In embodiments, thetransverse cross-section of the fiber can be characterized by a meanradius and the second region can comprise about 0.5% of the mean radiusof the fiber, for example, about 1%, about 2%, about 3%, about 5%, about7%, about 9%, about 10%, about 12%, about 15%, about 20%, about 25%,about 50%, about 75%, about 80%, about 85%, about 90%, about 92%, about94%, about 96%, or about 98%, for example in a range of about 1% toabout 98%, about 1% to about 90%, about 1% to about 75%, about 1% toabout 50%, about 1% to about 25%, about 1% to about 20% about 1% toabout 15%, about 1% to about 12% about 1% to about 10%, about 1% toabout 8%, about 1% to about 6%, about 1% to about 5%, about 1% to about4%, about 2% to about 25%, about 4% to about 25%, about 6% to about 35%,or about 8% to about 20%.

In embodiments, the polymer in the first, second, and optional thirdregions have the same degree of polymerization. In embodiments, thepolymer in the first, second, and optional third regions can have thesame degree of hydrolysis.

Although the fibers disclosed herein having a transverse cross-sectioncharacterized by a core-sheath structure or gradient degree ofmodification are described as having a greater degree of modification inthe sheath and/or surface region of the fiber, it will be understoodthat the fibers can be prepared such that the degree of modification inthe polymer of the sheath and/or surface region of the fiber is lessthan the degree of modification of the polymer of the core and/or innersurface region. Thus, the disclosure further provides a fiber having asurface region and an interior region. The fiber comprises a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety, e.g., only at least one vinyl acetate moiety, only at least onevinyl alcohol moiety, or both a vinyl acetate moiety and a vinyl alcoholmoiety, chemically modified with a modification agent. The fiber has atransverse cross-section including the surface region having a lesserdegree of modification than the degree of modification in the interiorregion. In embodiments, the disclosure provides a fiber having a surfaceregion and an interior region. The fiber comprises polyvinyl alcohol anda polyvinyl alcohol copolymer. The fiber has a transverse cross-sectionincluding the polymer of the surface region having a lesser degree ofmodification than the degree of modification in the interior region.

The fiber of the disclosure can have a transverse cross-section of thefiber having a decreasing gradient in the degree of modification of thepolymer from the interior region to the surface region. In embodiments,the fiber of the disclosure can have a transverse cross-section having adecreasing gradient in the degree of modification of the polyvinylalcohol copolymer from the interior region to the surface region.

Nonwoven Webs

The nonwoven webs of the disclosure are generally sheet-like structureshaving two exterior surfaces, the nonwoven webs including a plurality offibers. As used herein, and unless specified otherwise, the “exteriorsurface” of a nonwoven web refers to the faces of the sheet-likestructure, denoted 100 and 101 in FIG. 5. A nonwoven web generallyrefers to an arrangement of fibers bonded to one another, wherein thefibers are neither woven nor knitted. In general, the plurality offibers can be arranged in any orientation. In embodiments, the pluralityof fibers are arranged randomly (i.e., do not have an orientation). Inembodiments, the plurality of fibers are arranged in a unidirectionalorientation. In embodiments, the plurality of fibers are arranged in abidirectional orientation. In some embodiments, the plurality of fibersare multi-directional, having different arrangements in different areasof the nonwoven web. In embodiments, the nonwoven web can include asingle type of water-soluble fiber. In embodiments, the nonwoven web caninclude a single type of water-insoluble fiber. In embodiments, thenonwoven web can include a single type of water-soluble fiber and one ormore different types of water-insoluble fibers. In embodiments, thenonwoven web can include one or more different types of water-solublefibers and one or more different types of water-insoluble fibers. Inembodiments, the nonwoven web can consist of or consist essentially ofwater-soluble fibers. In embodiments, the nonwoven web can consist of orconsist essentially of water-insoluble fibers. In some embodiments, thenonwoven web can include a single type of fiber forming material (i.e.,all fibers have the same composition of fiber forming material), but caninclude fibers prepared by one or more fiber forming processes, e.g.,wet cooled gel spinning, thermoplastic fiber spinning, melt blowing,spun bonding, or a combination thereof. In some embodiments, thenonwoven web can include a single type of fiber forming material and thefibers are made from a single fiber forming process. In someembodiments, the nonwoven web can include two or more fiber formingmaterials (e.g., blends of fibers having different compositions of fiberforming materials, fibers including blends of fiber forming materials,or both) and the fibers can be prepared by one or more fiber formingprocesses, e.g., wet-cool gel spinning, thermoplastic fiber spinning,melt blowing, spun bonding, or a combination thereof. In someembodiments, the nonwoven web can include two or more fiber formingmaterials and the fibers are made from a single fiber forming process.In embodiments, the fibers of the nonwoven web can have substantiallythe same diameters or different diameters.

In embodiments wherein the nonwoven webs of the disclosure include ablend of fibers including a first fiber and a second fiber, the firstand second fibers can have a difference in length to diameter (L/D)ratio, tenacity, shape, rigidness, elasticity, solubility, meltingpoint, glass transition temperature (T_(g)), fiber forming material,color, or a combination thereof.

As is well understood in the art, the term machine-direction (MD) refersto the direction of web travel as the nonwoven web is produced, forexample on commercial nonwoven making equipment. Likewise, the termcross-direction (CD) refers to the direction in the plane of the webperpendicular to the machine-direction. With respect to nonwovencomposite articles, wipes, absorbent articles or other articlecomprising a nonwoven composite article of the disclosure, the termsrefer to the corresponding directions of the article with respect to thenonwoven web used to produce the article.

The tenacity of the nonwoven web can be the same or different from thetenacity of the fibers used to prepare the web. Without intending to bebound by theory, it is believed that the tenacity of the nonwoven web isrelated to the strength of the nonwoven web, wherein a higher tenacityprovides a higher strength to the nonwoven web. In general, the tenacityof the nonwoven web can be modified by using fibers having differenttenacities. The tenacity of the nonwoven web may also be affected byprocessing. In general, water-dispersible webs of the disclosure canhave relatively high tenacities, i.e., the water-dispersible nonwovenweb is a self-supporting web that can be used as the sole material forpreparing an article and/or pouch. In embodiments, the nonwoven web is aself-supporting web. In contrast, the nonwoven webs that are preparedaccording to melt blowing, electro-spinning, and/or rotary spinningprocesses typically have low tenacities, and may not be self-supportingor capable of being used as a sole web for forming an article or pouch.Thus, in some embodiments, the nonwoven web is not self-supporting andis used in combination with a second nonwoven web and/or water-solublefilm.

In embodiments, the nonwoven webs of the disclosure can have a ratio oftenacity in the machine direction to the tenacity in the cross direction(MD:CD) of in a range of about 0.5 to about 1.5, about 0.75 to about1.5, about 0.80 to about 1.25, about 0.90 to about 1.1, or about 0.95 toabout 1.05, or about 1. In embodiments, the nonwoven webs of thedisclosure have a tenacity ratio MD:CD of about 0.8 to about 1.25. Inembodiments the nonwoven webs of the disclosure have a tenacity ratioMD:CD of about 0.9 to about 1.1. In embodiments, the nonwoven webs ofthe disclosure have a tenacity of about 1. Without intending to be boundby theory, it is believed that as the tenacity ratio MD:CD approaches 1,the durability of the nonwoven is increased, providing superiorresistance to breakdown of the nonwoven when stress is applied to thenonwoven during use, e.g., scrubbing with a flushable wipe comprising anonwoven web of the disclosure, or pulling/tugging on the nonwovencaused by movement while wearing a wearable absorbent article.

The nonwoven webs of the disclosure have a rougher surface relative to awater-soluble film, which provides decreased contact between a surfaceand the nonwoven web than between a surface and the water-soluble film.Advantageously, this surface roughness can provide an improved feel tothe consumer (i.e., a cloth-like hand-feel instead of a rubberyhand-feel), improved aesthetics (i.e., less glossy than a water-solublefilm), and/or facilitate processability in preparing thermoformed,and/or vertical formed, filled, and sealed, and/or multichamber packetswhich require drawing the web along a surface of the processingequipment/mold. Accordingly, the fibers should be sufficiently coarse toprovide a surface roughness to the resulting nonwoven web without beingso coarse as to produce drag.

Nonwoven webs can be characterized by basis weight. The basis weight ofa nonwoven is the mass per unit area of the nonwoven. Basis weight canbe modified by varying manufacturing conditions, as is known in the art.A nonwoven web can have the same basis weight prior to and subsequent tobonding. Alternatively, the bonding method can change the basis weightof the nonwoven web. For example, wherein bonding occurs through theapplication of heat and pressure, the thickness of the nonwoven (and,thus, the area of the nonwoven) can be decreased, thereby increasing thebasis weight. For another example, bonding among fibers can also occurduring a through-air process at a suitable temperature, for example, ina range of from about 100° C. to about 200° C. (e.g., from 120° C. to180° C.). Accordingly, as used herein and unless specified otherwise,the basis weight of a nonwoven refers to the basis weight of thenonwoven subsequent to bonding.

The nonwoven webs of the disclosure can have any basis weight in a rangeof about 0.1 g/m² to about 700 g/m², about 0.5 g/m² to about 600 g/m²,about 1 g/m² to about 500 g/m², about 1 g/m² to about 400 g/m², about 1g/m² to about 300 g/m², about 1 g/m² to about 200 g/m², about 1 g/m² toabout 100 g/m², about 30 g/m² to about 100 g/m², about 20 g/m² to about100 g/m², about 20 g/m² to about 80 g/m², or about 25 g/m² to about 70g/m².

In embodiments, the nonwoven web can be carded and have a basis weightof about 5 g/m² to about 15 g/m², about 7 g/m² to about 13 g/m², about 9g/m² to about 11 g/m², or about 10 g/m². In embodiments, the nonwovenweb can be carded and can have a basis weight of 30 g/m² or more, forexample in a range of 30 g/m² to about 70 g/m², about 30 g/m² to about60 g/m², about 30 g/m² to about 50 g/m², about 30 g/m² to about 40 g/m²,or about 30 g/m² to about 35 g/m². In embodiments, the nonwoven web canbe melt-spun and have a basis weight in a range of about 1 g/m² to about20 g/m², about 2 g/m² to about 15 g/m², about 3 g/m² to about 10 g/m²,about 5 g/m² to about 15 g/m², about 7 g/m² to about 13 g/m², about 9g/m² to about 11 g/m², or about 10 g/m². In embodiments, the nonwovenweb can be melt-spun and can have a basis weight of about 0.1 g/m² toabout 10 g/m², about 0.1 g/m² to about 8 g/m², about 0.2 g/m² to about 6g/m², about 0.3 g/m² to about 4 g/m², about 0.4 g/m² to about 2 g/m², orabout 0.5 g/m² to about 1 g/m².

Related to the basis weight is the fiber volume density and porosity ofa nonwoven. Nonwoven webs, as prepared and prior to bonding, have afiber density of about 30% or less by volume, i.e., for a given volumeof nonwoven, 30% or less of the volume is made up of the fibers and theremaining volume is air. Thus, the nonwoven webs are highly porous.Fiber volume density and porosity of the nonwoven are inversely relatedcharacteristics of a nonwoven, for example, a nonwoven having a fibervolume density of about 30% by volume would have a porosity of about 70%by volume. It is well understood in the art that as the fiber volumedensity increases, the porosity decreases. Fiber volume density can beincreased by increasing the basis weight of a nonwoven, for example, bybonding through the application of heat and pressure or hot through-air,potentially reducing the thickness (and, thus, the volume) of thenonwoven. Accordingly, as used herein and unless specified otherwise,the fiber volume density and porosity of a nonwoven refers to the fibervolume density and porosity of the nonwoven subsequent to bonding.

The nonwoven webs of the disclosure can have any porosity in a range ofabout 50% to about 95%, for example, at least about 50%, at least about60%, at least about 70%, at least about 75%, or at least about 80% andup to about 95%, up to about 90%, up to about 85%, up to about 80%, upto about 75%, up to about 70%, or in a range of about 50% to about 95%,about 50% to about 80%, about 50% to about 70%, about 60% to about 75%,about 60% to about 80%, about 60% to about 90%, about 75% to about 85%,about 75% to about 90%, or about 75% to about 95%.

Pore sizes can be determined using high magnification and orderedsurface analysis techniques including, but not limited toBrunauer-Emmett-Teller theory (BET), small angle X-ray scattering(SAXS), and molecular adsorption.

The nonwoven webs of the disclosure can have any thickness. Suitablethicknesses can include, but are not limited to, about 5 to about 10,000μm (1 cm), about 5 to about 5,000 μm, about 5 to about 1,000 μm, about 5to about 500 μm, about 200 to about 500 μm, about 5 to about 200 μm,about 20 to about 100 μm, or about 40 to about 90 μm, or about 50 to 80μm, or about or about 60 to 65 μm for example 50 μm, 65 μm, 76 μm, or 88μm. The nonwoven webs of the disclosure can be characterized as highloft or low loft. In general, loft refers to the ratio of thickness tobasis weight. High loft nonwoven webs can be characterized by a highratio of thickness to basis weight. As used herein, “high loft” refersto a nonwoven web of the disclosure having a basis weight as definedherein and a thickness exceeding 200 μm. The thickness of the nonwovenweb can be determined by according to ASTM D5729-97, ASTM D5736, and ISO9073-2:1995 and can include, for example, subjecting the nonwoven web toa load of 2 N and measuring the thickness. High loft materials can beused according to known methods in the art, for example, thru-airbonding or cross-lapping, which uses a cross-lapper to fold theunbounded web over onto itself to build loft and basis weight. Withoutintending to be bound by theory, in contrast to water-soluble filmswherein the solubility of the film can be dependent on the thickness ofthe film; the solubility of a nonwoven web including water-solublefibers is not believed to be dependent on the thickness of the web. Inthis regard, it is believed that because the individual fibers provide ahigher surface area than a water soluble film, regardless of thethickness of the film, the parameter that limits approach of water tothe fibers and, thereby, dissolution of the fibers in a water-solublenonwoven web is the basis weight.

The water-solubility of the nonwoven webs of the disclosure can be afunction of the type of fiber(s) used to prepare the web as well as thebasis weight of the water-dispersible web. Without intending to be boundby theory, for a nonwoven web comprising a sole fiber type comprising asole fiber forming material, it is believed that the solubility profileof a nonwoven web follows the same solubility profile of the fiber(s)used to prepare the nonwoven web, and the solubility profile of thefiber follows the same solubility profile of the fiber formingpolymer(s) from which the fiber is prepared. For example, for nonwovenwebs comprising PVOH fibers, the degree of hydrolysis and the degree ofmodification of the PVOH or PVOH copolymer can be chosen such that thewater-solubility of the nonwoven web is also influenced. In general, ata given temperature, as the degree of modification of the PVOH or PVOHcopolymer increases, water solubility of the polymer generallyincreases.

Modification of PVOH or PVOH copolymer increases the solubility of thepolymer. Thus, it is expected that at a given temperature the solubilityof a water-dispersible nonwoven web prepared from a modified PVOHcopolymer, would be higher than that of a nonwoven web prepared from aPVOH copolymer without modification and having the same degree ofhydrolysis as the PVOH copolymer. Further, it is expected that at agiven temperature the solubility of a water dispersible nonwoven webprepared from a PVOH copolymer or a modified PVOH copolymer, that istreated by the methods as described herein to increase the degree ofmodification of the fibers, would be higher than that of a nonwoven webprepared without post-modification of the fibers as disclosed herein.Following these trends, a water-dispersible nonwoven web having specificsolubility characteristics can be designed. In some embodiments, thewater solubility of the fiber is maintained after modification with amodification agent, and the water solubility of the fiber can beapproximately the same before and after the chemical modification withthe modification agent.

Surprisingly, for a nonwoven web including a blend of fiber types, eachfiber type having a sole fiber forming material, the solubility of thenonwoven web does not follow the rule of mixtures as would be expectedfor a blend of fiber types. Rather, for a nonwoven web including blendof two fiber types, when the two fiber types were provided in a ratioother than 1:1, the solubility of the nonwoven tended toward thesolubility of the less soluble fiber (i.e., the fiber that requireshigher temperatures to completely dissolve, and dissolves more slowly attemperatures below the complete dissolution temperature). For nonwovenwebs including 1:1 blends of fibers, the solubility of the nonwoven webwas generally lower than the solubility of the nonwoven webs includingblends other than 1:1 blends (i.e., at a given temperature, the nonwovenwebs including the 1:1 blends took longer to rupture, disintegrate, anddissolve than the nonwoven webs including, e.g., 3:1 and 1:3 ratios offiber types). This trend was especially pronounced at temperatures lowerthan the complete dissolution temperature of the less soluble fiber.

Inclusion of a water-insoluble fiber in a nonwoven web can also be usedto design a nonwoven web having specific solubility and/or delayedrelease properties (e.g., when the nonwoven web is included in awater-dispersible pouch). Without intending to be bound by theory, it isbelieved that as the weight percent of water-insoluble fiber included ina nonwoven web is increased (based on the total weight of the nonwovenweb), the solubility of the nonwoven web generally decreases and thedelayed release properties of a pouch comprising a nonwoven webgenerally increase. Upon contact with water at a temperature at or abovethe solubility temperature of the water-soluble fiber, a nonwoven webcomprising a water-soluble fiber and water-insoluble fiber will begin tothin as the water-soluble fiber dissolves, thereby breaking down the webstructure and/or increasing the pore size of the pores of the nonwovenweb. In general, the larger the break-down of the web structure orincrease in the pore size, the faster the water can access the contentsof the pouch and the faster the contents of the pouch will be released.Similarly, delayed release of the contents of a pouch comprising thenonwoven web of the disclosure can be achieved by using a blend ofwater-soluble fibers having different solubility properties and/ordifferent solubility temperatures. In general, for nonwoven websincluding water-soluble fibers comprising a polyvinyl alcohol fiberforming materials, at water temperatures of 50% or more of the completedissolution temperature of the water-soluble fibers (e.g., at 40° C. fora fiber having a complete dissolution temperature of 70° C.), the fiberswill undergo polymer network swelling and softening, but the overallstructure will remain intact. In embodiments wherein the nonwoven webincludes a water-soluble fiber and a water-insoluble fiber, the ratio ofsoluble fiber to insoluble fiber is not particularly limited. Thewater-soluble fiber can comprise about 1% to about 99%, about 20% toabout 80%, about 40% to about 90%, about 50% to about 90%, or about 60%to about 90% by weight of the total weight of the fibers and thewater-insoluble fiber can comprise about 1% to about 99%, about 20% toabout 80%, about 10% to about 60%, about 10% to about 50%, or about 10%to about 40% by weight of the total weight of the fibers.

Further, as the basis weight of the nonwoven web increases the rate ofdissolution of the web decreases, provided the fiber composition andbonding parameters remain constant, as there is more material to bedissolved. For example, at a given temperature, a water-soluble webprepared from fibers comprising PVOH polymer(s) and having a basisweight of, e.g., 40 g/m², is expected to dissolve slower than anotherwise-identical nonwoven web having a basis weight of, e.g., 30g/m². This relationship was especially prominent when the temperature ofthe water for dissolution was lower than the complete dissolutiontemperature of the fibers that made up the nonwoven web. Accordingly,basis weight can also be used to modify the solubility characteristicsof the water-dispersible nonwoven web. The nonwoven web can generallyhave any basis weight in a range of about 1 g/m² to about 700 g/m²,about 1 g/m² to about 600 g/m², about 1 g/m² to about 500 g/m², about 1g/m² to about 400 g/m², about 1 g/m² to about 300 g/m², about 1 g/m² toabout 200 g/m², about 1 g/m² to about 100 g/m², about 30 g/m² to about100 g/m², about 20 g/m² to about 100 g/m², about 20 g/m² to about 80g/m², about 25 g/m² to about 70 g/m², or about 30 g/m² to about 70 g/m².

Additionally, calendar settings have a secondary impact on thesolubility profile of a nonwoven web of the disclosure. For example, fornonwoven webs having identical fiber chemistry and similar basisweights, at a given calendar pressure, the solubility time of a nonwovenweb generally increases with increasing calendar temperature. Thisrelationship was especially prominent when the temperature of the waterfor dissolution was lower than the complete dissolution temperature ofthe fibers that made up the nonwoven web.

Without intending to be bound by theory, it is believed that solubility(in terms of time to dissolution, for example according to MSTM-205) ofa water-soluble nonwoven web is expected to surpass that of awater-soluble film of the same size (L x W) and/or mass, prepared fromthe same PVOH polymer. This is due to the higher surface area found inthe nonwoven compared to a film, leading to faster solubilization.

The nonwoven web of the disclosure can include any of the auxiliaryagents disclosed herein. Auxiliary agents can be dispersed throughoutthe web, e.g., between fibers, or applied to one of more surfaces of thenonwoven web. Auxiliary agents can be added to the nonwoven web duringthe melt-spun process, using a “co-form” process developed by KimberlyClark, as is well known in the art. Auxiliary agents can also be addedto one or more faces of a nonwoven web or article prepared therefrom, byany suitable means.

In embodiments, the nonwoven webs of the disclosure are substantiallyfree of auxiliary agents. As used herein and unless specified otherwise,“substantially free of auxiliary agents” means that the nonwoven webincludes less than about 0.01 wt %, less than about 0.005 wt. %, or lessthan about 0.001 wt. % of auxiliary agents, based on the total weight ofthe nonwoven web.

In a one embodiment, one or more stationary powder spray guns are usedto direct an auxiliary agent powder stream towards the web or article,from one or more than one direction, while the web or article istransported through the coating zone by means of a belt conveyor. In analternative embodiment, an article is conveyed through a suspension ofan auxiliary agent powder in air. In yet another alternative embodiment,the articles are tumble-mixed with the auxiliary agent powder in atrough-like apparatus. In another embodiment, which can be combined withany other embodiment, electrostatic forces are employed to enhance theattraction between the auxiliary agent powder and the article. This typeof process can be based on negatively charging the powder particles anddirecting these charged particles to the grounded articles. In otheralternative embodiments, the auxiliary agent powder is applied to thearticle by a secondary transferring tool including, but not limited to,rotating brushes, which are in contact with the powder or by powderedgloves, which can transfer the powder from a container to the article.In yet another embodiment, the auxiliary agent powder is applied bydissolving or suspending the powder in a non-aqueous solvent or carrier,which is then atomized and sprayed onto the nonwoven or article. In onetype of embodiment, the solvent or carrier subsequently evaporates,leaving the auxiliary agent powder behind. In one class of embodiments,the auxiliary agent powder is applied to the nonwoven or article in anaccurate dose. This class of embodiments utilizes closed-system drylubricant application machinery, such as PekuTECH's powder applicator PM700 D. In this process the auxiliary agent powder, optionally batch-wiseor continuously, is fed to a feed trough of application machinery. Thenonwoven webs or articles are transferred from the output belt of astandard rotary drum pouch machine onto a conveyor belt of the powderapplication machine, wherein a controlled dosage of the auxiliary agentis applied to the nonwoven web or article.

Liquid auxiliary agents can be applied to a nonwoven web or article, forexample, by spin casting, spraying a solution such as an aerosolizedsolution, roll coating, flow coating, curtain coating, extrusion, knifecoating, or any combination thereof.

In embodiments, the nonwoven web can be colored, pigmented, and/or dyedto provide an improved aesthetic effect relative to water-soluble films.Suitable colorants can include an indicator dye, such as a pH indicator(e.g., thymol blue, bromothymol, thymolphthalein, and thymolphthalein),a moisture/water indicator (e.g., hydrochromic inks or leuco dyes), or athermochromic ink, wherein the ink changes color when temperatureincreases and/or decreases. Suitable colorants include, but are notlimited to, a triphenylmethane dye, an azo dye, an anthraquinone dye, aperylene dye, an indigoid dye, a food, drug and cosmetic (FD&C)colorant, an organic pigment, an inorganic pigment, or a combinationthereof. Examples of colorants include, but are not limited to, FD&C Red#40; Red #3; FD&C Black #3; Black #2; Mica-based pearlescent pigment;FD&C Yellow #6; Green #3; Blue #1; Blue #2; titanium dioxide (foodgrade); brilliant black; and a combination thereof.

When included in a water-soluble fiber, the colorant can be provided inan amount of 0.01% to 25% by weight of the water-soluble polymermixture, such as, 0.02%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%,8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%,23%, and 24% by weight of the water-soluble polymer mixture.

Advantageously, the nonwoven webs of the disclosure can demonstratepreferential shrinking in the presence of heat and/or water (e.g.,humidity). Accordingly, the nonwoven webs can be heat and/or watershrunk when formed into packets. Further advantageously, the nonwovenwebs of the disclosure can demonstrate increased robustness (i.e.,mechanical properties) and improved solubility performance after storagein high heat and moisture environments (e.g., 38° C. and 80% relativehumidity (RH)). Such increased robustness and improved solubilityperformance is surprising as the expectation based on compositionallysimilar water-soluble films is that the robustness and solubilityperformance would be unaffected by storage in high heat and moistureconditions. In particular, after removal of comparable water-solublefilms from a conditioning environment, the water-soluble films willre-equilibrate with the surrounding environment leading to no long termor permanent changes in the performance properties of the films.

The nonwoven web of the disclosure can be used as a single layer or canbe layered with other nonwoven webs and/or water-soluble films. In someembodiments, the nonwoven web includes a single layer of nonwoven web.In some embodiments, the nonwoven web is a multilayer nonwoven webcomprising two or more layers of nonwoven webs. The one or more layerscan be laminated to each other. In refinements of the foregoingembodiment, the two or more layers can be the same (e.g., be preparedfrom the same fibers and having the same basis weight). In refinementsof the foregoing embodiment, the two or more layers can be different(e.g., be prepared from different types of fibers and/or have differentbasis weights). In embodiments, the nonwoven web can be laminated to awater-soluble film. In refinements of the foregoing embodiments, thenonwoven web and water-soluble film can be prepared from the samepolymer (e.g., a PVOH copolymer a modified polymer having a specificviscosity, degree of hydrolysis, and amount of modification if amodified polymer). In refinements of the foregoing embodiments, thenonwoven web and water-soluble film can be prepared from differentpolymers (e.g., the polymer used to prepare the fibers of the nonwovenweb can have different fiber chemistries (e.g., modifications),viscosities, degree of polymerization, degree of hydrolysis and/orsolubility than the polymer that makes up the water-soluble film).Advantageously, multilayered nonwoven webs and laminates can be used totune the moisture vapor transmission rate (MVTR) of a pouch or packetmade therefrom. Multilayer materials can be prepared according tovarious processes known in the art, for example, melt extrusion, coating(e.g., solvent coating, aqueous coating, or solids coating), sprayadhesion, material transfer, hot lamination, cold lamination, andcombinations thereof.

A multilayer nonwoven web can have a basis weight that is the sum of thebasis weights of the individual layers. Accordingly, a multilayernonwoven web will take longer to dissolve than any of the individuallayers provided as a single layer. In embodiments, the multilayernonwoven can have a basis weight in a range of about 1 g/m² to about 100g/m². Additionally, without intending to be bound by theory, it isbelieved that when pore sizes and pore arrangements are heterogeneousbetween layers, the pores in each layer will not align, therebyproviding a multilayer nonwoven web having smaller pores than theindividual layers. Accordingly, a nonporous water-dispersible nonwovenweb can be prepared by layering multiple porous water-dispersiblenonwoven webs.

The nonwoven web can also be laminated to a water-soluble film. Thelaminate can be formed using any known methods in the art including, butnot limited to heat and pressure, hot through-air, chemical bonding,and/or solvent welding. Chemical bonding can include ionically orcovalently functionalizing a surface of the nonwoven web and/or asurface of the water-soluble film such that when the surface of thenonwoven web comes in contact with the surface of the water-soluble filma chemical reaction occurs and covalently bonds the nonwoven web andwater-soluble film together. The multilayer nonwoven web can includethree or more layers. In embodiments, the multilayer nonwoven web caninclude a first layer comprising a water-soluble film, a second layercomprising a nonwoven web, and a third layer comprising a water-solublefilm. In embodiments, the multilayer nonwoven web can include a firstlayer comprising a nonwoven web, a second layer comprising awater-soluble film, and a third layer comprising a nonwoven web.

Advantageously, the laminate can be prepared concurrently with pouchformation, e.g., using the heat applied during thermoforming to bond thenonwoven web and water-soluble film layers together. The water-solublefilm can have the same solubility and/or chemical compatibilitycharacteristics as the nonwoven web or the water-soluble film can havedifferent solubility and/or chemical compatibility characteristics fromthe nonwoven web. In embodiments, the water-soluble film has the samesolubility and/or chemical compatibility characteristics as the nonwovenweb. In some embodiments, the water-soluble film has differentsolubility and/or chemical compatibility characteristics from thenonwoven web. Advantageously, when the water-soluble film has differentsolubility and/or chemical compatibility characteristics from thenonwoven web the laminate can be used to form a pouch having an interiorsurface with a first solubility and/or chemical compatibility and anexterior surface having a second solubility and/or chemicalcompatibility.

The water-soluble film used for a laminate can generally be anywater-soluble film, e.g., one previously known in the art. The polymerused to form the water-soluble film can be any water-soluble polymer, orcombination thereof, e.g., one described herein. The water-soluble filmcan contain at least about 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70wt. %, 75 wt. %, 80 wt. %, 85 wt. %, or 90 wt. % and/or up to about 60wt. %, 70 wt. %, 80 wt. %, 90 wt. %, 95 wt. %, or 99 wt. % of awater-soluble polymer, e.g., a PVOH polymer, such as a PVOH copolymer,such a polymer modified with a modification agent, or any polymer blendthereof.

The water-soluble film can contain other auxiliary agents and processingagents, such as, but not limited to, plasticizers, plasticizercompatibilizers, surfactants, lubricants, release agents, fillers,extenders, cross-linking agents, antiblocking agents, antioxidants,detackifying agents, antifoams, nanoparticles such as layeredsilicate-type nanoclays (e.g., sodium montmorillonite), bleaching agents(e.g., sodium metabisulfite, sodium bisulfite or others), aversiveagents such as bitterants (e.g., denatonium salts such as denatoniumbenzoate, denatonium saccharide, and denatonium chloride; sucroseoctaacetate; quinine; flavonoids such as quercetin and naringen; andquassinoids such as quassin and brucine) and pungents (e.g., capsaicin,piperine, allyl isothiocyanate, and resinferatoxin), and otherfunctional ingredients, in amounts suitable for their intended purposes.Embodiments including plasticizers are preferred. The amount of suchagents can be up to about 50 wt. %, 20 wt %, 15 wt %, 10 wt %, 5 wt. %,4 wt % and/or at least 0.01 wt. %, 0.1 wt %, 1 wt %, or 5 wt % of thefilm, individually or collectively.

The disclosure further provides a method of treating a nonwoven webcomprising a plurality of fibers comprising a polymer comprising atleast one of a vinyl acetate moiety or a vinyl alcohol moiety. Themethod comprises contacting at least a portion of the nonwoven web witha modification agent and a solvent to chemically modify the polymer in aregion of each fiber therein with the modification agent or increase thedegree of modification of the polymer of the fibers of the portion ofthe nonwoven web. The method provides a modified nonwoven web. Inembodiments, the portion of the nonwoven web contacted with themodification agent can be a face of the nonwoven web. In embodiments,the contacting can be by immersion, spraying, transfer coating, wicking,foaming, brushing, rolling, humidification, vapor deposition, printing,or any combination thereof. In embodiments, the contacting occursconcurrently with bonding of the plurality of the fibers into thenonwoven web. In embodiments, the contacting and bonding compriseschemical bonding. In embodiments, the contacting and bonding comprisesheat activated catalysis. The polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety can be a polyvinyl acetatehomopolymer, polyvinyl alcohol homopolymer, a polyvinyl alcoholcopolymer, a modified polyvinyl alcohol copolymer, or any combinationthereof as disclosed herein. In embodiments, the polymer is selectedfrom a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, amodified polyvinyl alcohol copolymer, and any combination thereof. Inembodiments, the polyvinyl alcohol copolymer is a copolymer of vinylacetate and vinyl alcohol. In embodiments, the polyvinyl alcoholcopolymer comprises an anionically modified copolymer. In embodiments,the anionically modified copolymer comprises a carboxylate, a sulfonate,or a combination thereof. In embodiments, the fiber further comprises anadditional polymer. The modification agent can be any modification asdisclosed herein. In embodiments, the modification agent can comprise ananhydride, a carboxylic acid, an alcohol, an ester, an ether, a sulfonicacid, a sulfonate, a click chemistry reagent, an amide, an amine, alactam, a nitrile, a ketone, an allyl compound, an acetyl containingcompound, a halogen containing compound, an alkyl containing compound,an imide, an acetal containing compound, an enolate, a nitro, a silane,an aziridine, an isocyanate, or a combination thereof. In embodiments,the modification agent can comprise an anhydride. Examples of a suitableanhydride are described above. In embodiments, the modification agent isprovided in an amount of about 0.2% to about 75% (w/w) based on theweight of the solvent. In embodiments, the fiber is not soluble in thesolvent prior to treatment, during treatment, and after treatment. Inembodiments, the modification agent further comprises an activator asdescribed herein.

The disclosure further provides a nonwoven web treated according to themethod of the disclosure. The disclosure provides a nonwoven webcomprising a plurality of fibers as described herein. The disclosureprovides a multilayer nonwoven web comprising a first layer comprising anonwoven web treated according to the method of the disclosure or anonwoven web comprising the plurality of fibers of the disclosure. Thepolymer of the fibers in the nonwoven web is chemically modified, forexample, bonded with the moiety of the modification agent throughchemical reaction, for example, the reaction between the hydroxyl group(—OH) in the vinyl alcohol moiety and the modification agent.

Biodegradability

Polyvinyl alcohol polymers are biodegradable as they decompose in thepresence of water and enzymes under aerobic, anaerobic, soil, andcompost conditions (in the presence of water). In general, as the degreeof hydrolysis of a polyvinyl alcohol polymer increases up to about 80%,the biodegradation activity of the polyvinyl alcohol polymer increases.Without intending to be bound by theory, it is believed that increasingthe degree of hydrolysis above 80% does not appreciably affectbiodegradability. Additionally, the stereoregularity of the hydroxylgroups of polyvinyl alcohol polymers has a large effect on thebiodegradability activity level and the more isotactic the hydroxylgroups of the polymer sequence, the higher degradation activity becomes.Without intending to be bound by theory, for soil and/or compostbiodegradation it is believed that a nonwoven web prepared from apolyvinyl alcohol fiber will have higher biodegradation activity levelsrelative to a water-soluble film prepared from a similar polyvinylalcohol polymer, due to the increase in the polymer surface areaprovided by the nonwoven web, relative to a film. Further, withoutintending to be bound by theory, it is believed that while the degree ofpolymerization of the polyvinyl alcohol polymer has little to no effecton the biodegradability of a film or nonwoven web prepared with thepolymer, the polymerization temperature may have an effect on thebiodegradability of a film or nonwoven because the polymerizationtemperature can affect the crystallinity and aggregating status of apolymer. In particular as the crystallinity decreases, the polymer chainhydroxyl groups become less aligned in the polymer structure and thepolymer chains become more disordered allowing for chains to accumulateas amorphous aggregates, thereby decreasing availability of orderedpolymer structures such that the biodegradation activity is expected todecrease for soil and/or compost biodegradation mechanisms wherein thepolymer is not dissolved. Without intending to be bound by theory, it isbelieved that because the stereoregularity of the hydroxyl groups ofpolyvinyl alcohol polymers has a large effect on biodegradabilityactivity levels, the substitution of functionalities other than hydroxylgroups, such as with a modification agent (e.g., anionic AMPS functionalgroups, carboxylate groups, lactone groups, or the like) is expected todecrease the biodegradability activity level, relative to a polyvinylalcohol copolymer without modification and having the same degree ofhydrolysis, unless the functional group itself is also biodegradable, inwhich case biodegradability of the polymer can be increased withsubstitution. Further, it is believed that while the biodegradabilityactivity level of a substituted polyvinyl alcohol can be less than thatof the corresponding homopolymer, the substituted polyvinyl alcohol willstill exhibit biodegradability.

Methods of determining biodegradation activity are known in the art, forexample, as described in Chiellini et al., Progress in Polymer Science,Volume 28, Issue 6, 2003, pp. 963-1014, which is incorporated herein byreference in its entirety. Further methods and standards can be found inECHA's Annex XV Restriction Report—Microplastics, Version number 1, Jan.11, 2019, which is incorporated herein by reference in its entirety.Suitable standards include OECD 301B (ready biodegradability), OECD 301B(enhanced biodegradation), OECD 302B (inherent biodegradability), OECD311(anaerobic), ASTM D5988 (soil).

In embodiments, the fibers and nonwoven webs of the disclosure can be ofthe standard ready biodegradation, enhanced biodegradation, or inherentbiodegradation. As used herein, the term “ready biodegradation” refersto a standard that is met if the material (e.g., a fiber) reached 60%biodegradation (mineralization) within 28 days of the beginning of thetest, according to the OECD 301B test as described in said ECHA's AnnexXV. As used herein, the term “enhanced biodegradation” refers to astandard that is met if the material (e.g., a fiber) reaches 60%biodegradation within 60 days from the beginning of the test, accordingto the OECD 301B test as described in said ECHA's Annex XV. Inembodiments, the fibers and nonwoven webs of the disclosure meet thestandards of ready biodegradation. In embodiments, the fibers andnonwoven webs of the disclosure meet the standards of readybiodegradation or enhanced degradation. In embodiments, the fibers andnonwoven webs of the disclosure meet the standards of inherentbiodegradation. In embodiments, the fibers and nonwoven webs of thedisclosure meet the standards of enhanced degradation. In embodiments,the fibers and nonwoven webs of the disclosure meet the standards ofinherent biodegradation, enhanced biodegradation, or readybiodegradation. In embodiments, the laminate (nonwoven and film) of thedisclosure meet the standards of ready biodegradation or enhancedbiodegradation.

Uses

The nonwoven webs of the disclosure are suitable for a variety ofcommercial applications. Suitable commercial applications for thenonwoven webs of the disclosure can include, but are not limited to,water-dispersible or flushable pouches and packets; medical uses such assurgical masks, medical packaging, shoe covers, wound dressing, and drugdelivery; filtration systems such as for gasoline and oil, mineralprocessing, vacuum bags, air filters, and allergen membranes orlaminates; personal care products such as for baby wipes, makeupremoving wipes, exfoliating clothes, makeup applicators, and wearableabsorbent articles such as diapers and adult incontinence products;office products such as shopping bags or envelopes; and others such aslens cleaning wipes, cleanroom wipes, potting material for plants,antibacterial wipes, agricultural seed strips, fabric softener sheets,garment/laundry bags, food wrapping, floor care wipes, pet care wipes,polishing tools, dust removal, and hand cleaning.

Sealed Pouches

The disclosure further provides a pouch comprising a nonwoven webaccording to the disclosure in the form of a pouch defining an interiorpouch volume. In some embodiments, the pouch can include a laminatecomprising a water-soluble film and a nonwoven web of the disclosure.The pouch can be a water-dispersible pouch, optionally a water-solublepouch and/or a flushable pouch. The disclosure further provides a methodof preparing a packet comprising a nonwoven web of the disclosure, themethod comprising forming a nonwoven web into the form of a pouch,filling the pouch with a composition to be enclosed therein, and sealingthe pouch to form a packet. In some embodiments, sealing includes heatsealing, solvent welding, adhesive sealing, or a combination thereof.

The nonwoven webs and laminates disclosed herein are useful for creatinga sealed article in the form of a pouch defining an interior pouchvolume to contain a composition therein for release into an aqueousenvironment. A “sealed article” optionally encompasses sealedcompartments having a vent hole, for example, in embodiments wherein thecompartment encloses a solid that off-gasses, but more commonly will bea completely sealed compartment.

The pouches may comprise a single compartment or multiple compartments.A pouch can be formed from two layers of nonwoven web or laminate sealedat an interface, or by a single nonwoven web or laminate that is foldedupon itself and sealed. The nonwoven web or laminate forms at least onesidewall of the pouch, optionally the entire pouch, and preferably anouter surface of the at least one sidewall. In another type ofembodiment, the nonwoven web or laminate forms an inner wall of thepacket, e.g., as a dividing wall between compartments. The nonwoven webor laminate can also be used in combination with a water-soluble film,e.g., as an exterior wall, inner wall, and/or compartment lid.

The composition enclosed in the pouch is not particularly limited, forexample including any of the variety of compositions described herein.In embodiments comprising multiple compartments, each compartment maycontain identical and/or different compositions. In turn, thecompositions may take any suitable form including, but not limited toliquid, solid, gel, paste, mull, pressed solids (tablets) andcombinations thereof (e.g., a solid suspended in a liquid).

In some embodiments, the pouches comprise multiple compartments. Themultiple compartments are generally superposed such that thecompartments share a partitioning wall interior to the pouch. Thecompartments of multi-compartment pouches may be of the same ordifferent size(s) and/or volume(s). The compartments of the presentmulti-compartment pouches can be separate or conjoined in any suitablemanner. In embodiments, the second and/or third and/or subsequentcompartments are superimposed on the first compartment. In oneembodiment, the third compartment may be superimposed on the secondcompartment, which is in turn superimposed on the first compartment in asandwich configuration. Alternatively, the second and third compartmentsmay be superimposed on the first compartment. However it is also equallyenvisaged that the first, the second and/or third and/or subsequentcompartments are orientated side-by-side or in concentric orientations.The compartments may be packed in a string, each compartment beingindividually separable by a perforation line. Hence, each compartmentmay be individually torn-off from the remainder of the string by theend-user. In some embodiments, the first compartment may be surroundedby at least the second compartment, for example in a tire-and-rimconfiguration, or in a pouch-in-a-pouch configuration.

The geometry of the compartments may be the same or different. Inembodiments the optionally third and subsequent compartments each have adifferent geometry and shape as compared to the first and secondcompartment. In these embodiments, the optionally third and subsequentcompartments are arranged in a design on the first or secondcompartment. The design may be decorative, educative, or illustrative,for example to illustrate a concept or instruction, and/or used toindicate origin of the product.

Methods of Making Pouches

Pouches and packets may be made using any suitable equipment and method.For example, single compartment pouches may be made using vertical formfilling, horizontal form filling, or rotary drum filling techniquescommonly known in the art. Such processes may be either continuous orintermittent. The nonwoven web, layered nonwoven web and film, orlaminate structure may be dampened, and/or heated to increase themalleability thereof. The method may also involve the use of a vacuum todraw the nonwoven web, layered nonwoven web and film, or laminatestructure into a suitable mold. The vacuum drawing the nonwoven web orlaminate into the mold can be applied for about 0.2 to about 5 seconds,or about 0.3 to about 3, or about 0.5 to about 1.5 seconds, once thenonwoven web, layered nonwoven web and film, or laminate structure is onthe horizontal portion of the surface. This vacuum can be such that itprovides an under-pressure in a range of 10 mbar to 1000 mbar, or in arange of 100 mbar to 600 mbar, for example.

The molds, in which packets may be made, can have any shape, length,width and depth, depending on the required dimensions of the pouches.The molds may also vary in size and shape from one to another, ifdesirable. For example, the volume of the final pouches may be about 5ml to about 300 ml, or about 10 ml to 150 ml, or about 20 ml to about100 ml, and that the mold sizes are adjusted accordingly.

Thermoforming

A thermoformable nonwoven web or laminate is one that can be shapedthrough the application of heat and a force. Thermoforming a nonwovenweb, layered nonwoven web and film, or laminate structure is the processof heating the nonwoven web, layered nonwoven web and film, or laminatestructure, shaping it (e.g., in a mold), and then allowing the resultingnonwoven web or laminate to cool, whereupon the nonwoven web or laminatewill hold its shape, e.g., the shape of the mold. The heat may beapplied using any suitable means. For example, the nonwoven web orlaminate may be heated directly by passing it under a heating element orthrough hot air, prior to feeding it onto a surface or once on asurface. Alternatively, it may be heated indirectly, for example byheating the surface or applying a hot item onto the nonwoven web orlaminate. In embodiments, the nonwoven web or laminate is heated usingan infrared light. The nonwoven web or laminate may be heated to atemperature in a range of about 50° C. to about 200° C., about 50° C. toabout 170° C., about 50° C. to about 150° C., about 50° C. to about 120°C., about 60° C. to about 130° C., about 70° C. to about 120° C., orabout 60° C. to about 90° C. Thermoforming can be performed by any oneor more of the following processes: the manual draping of a thermallysoftened nonwoven web or laminate over a mold, or the pressure inducedshaping of a softened nonwoven web or laminate to a mold (e.g., vacuumforming), or the automatic high-speed indexing of a freshly extrudedsheet having an accurately known temperature into a forming and trimmingstation, or the automatic placement, plug and/or pneumatic stretchingand pressuring forming of a nonwoven web or laminate.

Alternatively, the nonwoven web or laminate can be wetted by anysuitable means, for example directly by spraying a wetting agent(including water, a polymer composition, a plasticizer for the nonwovenweb or laminate composition, or any combination of the foregoing) ontothe nonwoven web or laminate, prior to feeding it onto the surface oronce on the surface, or indirectly by wetting the surface or by applyinga wet item onto the nonwoven web or laminate.

Once a nonwoven web or laminate has been heated and/or wetted, it may bedrawn into an appropriate mold, preferably using a vacuum. The fillingof the molded nonwoven web or laminate can be accomplished by utilizingany suitable means. In embodiments, the most preferred method willdepend on the product form and required speed of filling. Inembodiments, the molded nonwoven web or laminate is filled by in-linefilling techniques. The filled, open packets are then closed forming thepouches, using a second nonwoven web or laminate, by any suitablemethod. This may be accomplished while in horizontal position and incontinuous, constant motion. The closing may be accomplished bycontinuously feeding a second nonwoven web or laminate, preferablywater-soluble nonwoven web or laminate, over and onto the open packetsand then preferably sealing the first and second nonwoven web orlaminate together, typically in the area between the molds and thusbetween the packets.

Sealing the Pouches

Any suitable method of sealing the pouch and/or the individualcompartments thereof may be utilized. Non-limiting examples of suchmeans include heat sealing, solvent welding, solvent or wet sealing, andcombinations thereof. Typically, only the area that is to form the sealis treated with heat or solvent. The heat or solvent can be applied byany method, typically on the closing material, and typically only on theareas which are to form the seal. If solvent or wet sealing or weldingis used, it may be preferred that heat is also applied. Preferred wet orsolvent sealing/welding methods include selectively applying solventonto the area between the molds, or on the closing material, by forexample, spraying or printing this onto these areas, and then applyingpressure onto these areas, to form the seal. Sealing rolls and belts(optionally also providing heat) can be used, for example.

In embodiments, an inner nonwoven web or laminate is sealed to outernonwoven web(s) or laminate(s) by solvent sealing. The sealing solutionis generally an aqueous solution. In embodiments, the sealing solutionincludes water. In embodiments, the sealing solution includes water andfurther includes one or more polyols, diols and/or glycols such as1,2-ethanediol (ethylene glycol), 1,3-propanediol, 1,2-propanediol,1,4-butanediol (tetramethylene glycol), 1,5-pantanediol (pentamethyleneglycol), 1,6-hexanediol (hexamethylene glycol), 2,3-butanediol,1,3-butanediol, 2-methyl-1,3-propanediol, various polyethylene glycols(e.g., diethylene glycol, triethylene glycol), and combinations thereof.In embodiments, the sealing solution includes erythritol, threitol,arabitol, xylitol, ribitol, mannitol, sorbitol, galactitol, fucitol,iditol, inositol, volemitol, isomal, maltitol, lactitol, or anycombination thereof. In embodiments, the sealing solution includes awater-soluble polymer.

The sealing solution can be applied to the interfacial areas of theinner nonwoven web or laminate in any amount suitable to adhere theinner and outer nonwoven webs or laminates. As used herein, the term“coat weight” refers to the amount of sealing solution applied to thenonwoven web or laminate in grams of solution per square meter ofnonwoven web or laminate. In general, when the coat weight of thesealing solvent is too low, the nonwoven webs or laminates do notadequately adhere and the risk of pouch failure at the seams increases.Further, when the coat weight of the sealing solvent is too high, therisk of the solvent migrating from the interfacial areas increases,increasing the likelihood that etch holes may form in the sides of thepouches. The coat weight window refers to the range of coat weights thatcan be applied to a given film while maintaining both good adhesion andavoiding the formation of etch holes. A broad coat weight window isdesirable as a broader window provides robust sealing under a broadrange of operations. Suitable coat weight windows are at least about 3g/m², or at least about 4 g/m², or at least about 5 g/m², or at leastabout 6 g/m².

Cutting the Packets

Formed packets may be cut by a cutting device. Cutting can beaccomplished using any known method. It may be preferred that thecutting is also done in continuous manner, and preferably with constantspeed and preferably while in horizontal position. The cutting devicecan, for example, be a sharp item, or a hot item, or a laser, whereby inthe latter cases, the hot item or laser ‘burns’ through the film/sealingarea.

Forming and Filling Multi-Compartment Pouches

The different compartments of a multi-compartment pouches may be madetogether in a side-by-side style or concentric style wherein theresulting, cojoined pouches may or may not be separated by cutting.Alternatively, the compartments can be made separately.

In embodiments, pouches may be made according to a process comprisingthe steps of: a) forming a first compartment (as described above); b)forming a recess within or all of the closed compartment formed in step(a), to generate a second molded compartment superposed above the firstcompartment; c) filling and closing the second compartments by means ofa third nonwoven web, laminate, or film; d) sealing the first, secondand third nonwoven web, laminate, or film; and e) cutting the nonwovenwebs or laminates to produce a multi-compartment pouch. The recessformed in step (b) may be achieved by applying a vacuum to thecompartment prepared in step (a).

In embodiments, second, and/or third compartment(s) can be made in aseparate step and then combined with the first compartment as describedin European Patent Application Number 08101442.5 or U.S. PatentApplication Publication No. 2013/240388 A1 or WO 2009/152031.

In embodiments, pouches may be made according to a process comprisingthe steps of: a) forming a first compartment, optionally using heatand/or vacuum, using a first nonwoven web or laminate on a first formingmachine; b) filling the first compartment with a first composition; c)optionally filling the second compartment with a second composition; d)sealing the first and optional second compartment with a second nonwovenweb or laminate to the first nonwoven web or laminate; and e) cuttingthe nonwoven webs or laminates to produce a multi-compartment pouch.

In embodiments, pouches may be made according to a process comprisingthe steps of: a) forming a first compartment, optionally using heatand/or vacuum, using a first nonwoven web or laminate on a first formingmachine; b) filling the first compartment with a first composition; c)on a second forming machine, deforming a second nonwoven web orlaminate, optionally using heat and vacuum, to make a second andoptionally third molded compartment; d) filling the second andoptionally third compartments; e) sealing the second and optionallythird compartment using a third nonwoven web or laminate; f) placing thesealed second and optionally third compartments onto the firstcompartment; g) sealing the first, second and optionally thirdcompartments; and h) cutting the nonwoven web or laminate to produce amulti-compartment pouch.

The first and second forming machines may be selected based on theirsuitability to perform the above process. In embodiments, the firstforming machine is preferably a horizontal forming machine, and thesecond forming machine is preferably a rotary drum forming machine,preferably located above the first forming machine.

It should be understood that by the use of appropriate feed stations, itmay be possible to manufacture multi-compartment pouches incorporating anumber of different or distinctive compositions and/or different ordistinctive liquid, gel or paste compositions.

In embodiments, the nonwoven web or laminate and/or pouch is sprayed ordusted with a suitable material, such as an active agent, a lubricant,an aversive agent, or mixtures thereof. In embodiments, the nonwoven webor laminate and/or pouch is printed upon, for example, with an inkand/or an active agent.

Vertical Form, Fill and Seal

In embodiments, the nonwoven web or laminate of the disclosure can beformed into a sealed article. In embodiments, the sealed article is avertical form, filled, and sealed article. The vertical form, fill, andseal (VFFS) process is a conventional automated process. VFFS includesan apparatus such as an assembly machine that wraps a single piece ofthe nonwoven web or laminate around a vertically oriented feed tube. Themachine heat seals or otherwise secures the opposing edges of thenonwoven web or laminate together to create the side seal and form ahollow tube of nonwoven web or laminate. Subsequently, the machine heatseals or otherwise creates the bottom seal, thereby defining a containerportion with an open top where the top seal will later be formed. Themachine introduces a specified amount of flowable product into thecontainer portion through the open top end. Once the container includesthe desired amount of product, the machine advances the nonwoven web orlaminate to another heat sealing device, for example, to create the topseal. Finally, the machine advances the nonwoven web or laminate to acutter that cuts the film immediately above the top seal to provide afilled package.

During operation, the assembly machine advances the nonwoven web orlaminate from a roll to form the package. Accordingly, the nonwoven webor laminate must be able to readily advance through the machine and notadhere to the machine assembly or be so brittle as to break duringprocessing.

Pouch Contents

In any embodiment, the pouch can contain (enclose) a composition in thedefined interior volume of the pouch. The composition can be selectedfrom a liquid, solid or combination thereof. In embodiments wherein thecomposition includes a liquid, the nonwoven web can be a nonporousnonwoven web or a porous nonwoven web laminated with a water-solublefilm, the water-soluble film forming the inner surface of the pouch. Inembodiments wherein the composition is a solid, the pouch can comprise anonporous nonwoven web, a porous nonwoven web laminated with awater-soluble film, or a porous nonwoven web. In embodiments wherein thepouch includes a porous nonwoven web, the particle size of the solidcomposition is smaller than the pore size of the nonwoven web.

In embodiments, the sealed articles of the disclosure can enclose in theinterior pouch volume a composition comprising a liquid laundrydetergent, an agricultural composition, an automatic dish washingcomposition, household cleaning composition, a water-treatmentcomposition, a personal care composition, a food and nutritivecomposition, an industrial cleaning composition, a medical composition,a disinfectant composition, a pet composition, an office composition, alivestock composition, an industrial composition, a marine composition,a mercantile composition, a military composition, a recreationalcomposition, or a combination thereof. In embodiments, thewater-dispersible sealed articles of the disclosure can enclose in theinterior pouch volume a composition comprising a liquid laundrydetergent, an agricultural composition, an automatic dish washingcomposition, a household cleaning composition, a water-treatmentcomposition, a personal care composition, a food and nutritivecomposition, an industrial cleaning composition, or a combinationthereof. In embodiments, the water-dispersible sealed articles of thedisclosure can enclose in the interior pouch volume a compositioncomprising a liquid laundry detergent, an agricultural composition, anautomatic dish washing composition, a household cleaning composition, awater-treatment composition, a personal care composition, or acombination thereof. In embodiments, the water-dispersible sealedarticles of the disclosure can enclose in the interior pouch volume acomposition comprising an agricultural composition or a water-treatmentcomposition.

As used herein, “liquid” includes free-flowing liquids, as well aspastes, gels, foams and mousses. Non-limiting examples of liquidsinclude light duty and heavy duty liquid detergent compositions, dishdetergent for hand washing and/or machine washing; hard surface cleaningcompositions, fabric enhancers, detergent gels commonly used forlaundry, bleach and laundry additives, shaving creams, skin care, haircare compositions (shampoos and conditioners), and body washes. Suchdetergent compositions may comprise a surfactant, a bleach, an enzyme, aperfume, a dye or colorant, a solvent and combinations thereof.Optionally, the detergent composition is selected from the groupconsisting of a laundry detergent, a dishwashing detergent, a hardsurface cleaning composition, fabric enhancer compositions, shavingcreams, skin care, hair care compositions (shampoos and conditioners),and body washes, and combinations thereof.

Non-limiting examples of liquids include agricultural compositions,automotive compositions, aviation compositions, food and nutritivecompositions, industrial compositions, livestock compositions, marinecompositions, medical compositions, mercantile compositions, militaryand quasi-military compositions, office compositions, recreational andpark compositions, pet compositions, and water-treatment compositions,including cleaning and detergent compositions applicable to any suchuse.

Gases, e.g., suspended bubbles, or solids, e.g., particles, may beincluded within the liquids. A “solid” as used herein includes, but isnot limited to, powders, agglomerates, and mixtures thereof.Non-limiting examples of solids include: granules, micro-capsules,beads, noodles, and pearlised balls. Solid compositions may provide atechnical benefit including, but not limited to, through-the-washbenefits, pre-treatment benefits, and/or aesthetic effects.

The composition may be a non-household care composition. For example, anon-household care composition can be selected from agriculturalcompositions, aviation compositions, food and nutritive compositions,industrial compositions, livestock compositions, marine compositions,medical compositions, mercantile compositions, military andquasi-military compositions, office compositions, recreational and parkcompositions, pet compositions, and water-treatment compositions,including cleaning and detergent compositions applicable to any such usewhile excluding fabric and household care compositions

In one type of embodiment, the composition can include an agrochemical,e.g., one or more insecticides, fungicides, herbicides, pesticides,miticides, repellants, attractants, defoliaments, plant growthregulators, fertilizers, bactericides, micronutrients, and traceelements. Suitable agrochemicals and secondary agents are described inU.S. Pat. Nos. 6,204,223 and 4,681,228 and EP 0989803 A1. For example,suitable herbicides include paraquat salts (for example paraquatdichloride or paraquat bis(methylsulphate), diquat salts (for examplediquat dibromide or diquat alginate), and glyphosate or a salt or esterthereof (such as glyphosate isopropylammonium, glyphosate sesquisodiumor glyphosate trimesium, also known as sulfosate). Incompatible pairs ofcrop protection chemicals can be used in separate chambers, for exampleas described in U.S. Pat. No. 5,558,228. Incompatible pairs of cropprotection chemicals that can be used include, for example, bensulfuronmethyl and molinate; 2,4-D and thifensulfuron methyl; 2,4-D and methyl2-[[[[N-4-methoxy-6-methyl-1,3,5-triazine-2-yl)-N-methylamino]carbonyl]amino]-sulfonyl]benzoate;2,4-D and metsulfuron methyl; maneb or mancozeb and benomyl; glyphosateand metsulfuron methyl; tralomethrin and any organophosphate such asmonocrotophos or dimethoate; bromoxynil andN-[[4,6-dimethoxypyrimidine-2-yl)-amino]carbonyl]-3-(ethylsulfonyl)-2-pyridine-sulfonamide;bromoxynil and methyl2-[[[[(4-methyl-6-methoxy)-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]-benzoate;bromoxynil and methyl2-[[[[N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-N-methylamino]carbonyl]amino]-sulfonyl]benzoate.In another, related, type of embodiment, the composition can include oneor more seeds, optionally together with soil, and further optionallytogether with one or more additional components selected from mulch,sand, peat moss, water jelly crystals, and fertilizers, e.g., includingtypes of embodiments described in U.S. Pat. No. 8,333,033.

In another type of embodiment, the composition is a water-treatmentagent. Such agents can include harsh chemicals, such as aggressiveoxidizing chemicals, e.g., as described in U.S. Patent ApplicationPublication No. 2014/0110301 and U.S. Pat. No. 8,728,593. For example,sanitizing agents can include hypochlorite salts such as sodiumhypochlorite, calcium hypochlorite, and lithium hypochlorite;chlorinated isocyanurates such as dichloroisocyanuric acid (alsoreferred to as “dichlor” or dichloro-s-triazinetrione,1,3-dichloro-1,3,5-triazinane-2,4,6-trione) and trichloroisocyanuricacid (also referred to as “trichlor” or1,3,5-trichloro-1,3,5-triazinane-2,4,6-trione). Salts and hydrates ofthe sanitizing compounds are also contemplated. For example,dichloroisocyanuric acid may be provided as sodium dichloroisocyanurate,sodium dichloroisocyanurate acid dihydrate, among others. Brominecontaining sanitizing agents may also be suitable for use in unit dosepackaging applications, such as 1,3-dibromo-5,5-dimethylhydantoin(DBDMH), 2,2-dibromo-3-nitrilopropionamide (DBNPA), dibromocyano aceticacid amide, 1-bromo-3-chloro-5,5-dimethylhydantoin; and2-bromo-2-nitro-1,3-propanediol, among others. The oxidizing agent canbe one described in U.S. Pat. No. 7,476,325, e.g., potassium hydrogenperoxymonosulfate. The composition can be a pH-adjusting chemical, e.g.,as described in U.S. Patent Application Publication No. 2008/0185347,and can include, for example, an acidic component and an alkalinecomponent such that the composition is effervescent when contacted withwater, and adjusts the water pH. Suitable ingredients include sodiumbicarbonate, sodium bisulfate, potassium hydroxide, sulfamic acid,organic carboxylic acids, sulfonic acids, and potassium dihydrogenphosphate. A buffer blend can include boric acid, sodium carbonate,glycolic acid, and oxone monopersulfate, for example.

A water-treatment agent can be or can include a flocculant, e.g., asdescribed in U.S. Patent Application Publication No. 2014/0124454. Theflocculant can include a polymer flocculant, e.g., polyacrylamide, apolyacrylamide copolymer such as an acrylamide copolymers ofdiallydimethylammonium chloride (DADMAC), dimethylaminoethylacrylate(DMAEA), dimethylaminoethylmethacrylate (DMAEM),3-methylamidepropyltrimethylammonium chloride (MAPTAC) or acrylic acid;a cationic polyacrylamide; an anionic polyacrylamide; a neutralpolyacrylamide; a polyamine; polyvinylamine; polyethylene imine;polydimethyldiallylammonium chloride; poly oxyethylene; polyvinylalcohol; polyvinyl pyrrolidone; polyacrylic acid; polyphosphoric acid;polystyrene sulfonic acid; or any combination thereof. A flocculant canbe selected from chitosan acetate, chitosan lactate, chitosan adipate,chitosan glutamate, chitosan succinate, chitosan malate, chitosancitrate, chitosan fumarate, chitosan hydrochloride, and combinationsthereof. The water-treating composition can include a phosphate removingsubstance, e.g., one or more selected from a zirconium compound, a rareearth lanthanide salt, an aluminum compound, an iron compound, or anycombination thereof.

The composition can be a limescale removing composition, e.g., citric ormaleic acid or a sulfate salt thereof, or any mixture thereof, e.g., asdescribed in U.S. Patent Application No. 2006/0172910.

Various other types of compositions are contemplated for use in thepackets described herein, including particulates, for example downfeathers, e.g., as described in U.S. RE29059 E; super absorbentpolymers, e.g., as described in U.S. Patent Application Publication Nos.2004/0144682 and 2006/0173430; pigments and tinters, e.g., as describedin U.S. Pat. No. 3,580,390 and U.S. Patent Application Publication No.2011/0054111; brazing flux (e.g., alkali metal fluoroaluminates, alkalimetal fluorosilicates and alkali metal fluorozincates), e.g., asdescribed in U.S. Pat. No. 8,163,104; food items (e.g., coffee powder ordried soup) as described in U.S. Patent Application Publication No.2007/0003719; and wound dressings, e.g., as described in U.S. Pat. No.4,466,431.

In pouches comprising laundry, laundry additive and/or fabric enhancercompositions, the compositions may comprise one or more of the followingnon-limiting list of ingredients: fabric care benefit agent; detersiveenzyme; deposition aid; rheology modifier; builder; bleach; bleachingagent; bleach precursor; bleach booster; bleach catalyst; perfume and/orperfume microcapsules (see for example U.S. Pat. No. 5,137,646); perfumeloaded zeolite; starch encapsulated accord; polyglycerin esters;whitening agent; pearlescent agent; enzyme stabilizing systems;scavenging agents including fixing agents for anionic dyes, complexingagents for anionic surfactants, and mixtures thereof; opticalbrighteners or fluorescers; polymer including but not limited to soilrelease polymer and/or soil suspension polymer; dispersants; antifoamagents; non-aqueous solvent; fatty acid; suds suppressors, e.g.,silicone suds suppressors (see: U.S. Patent Application Publication No.2003/0060390 A1, ¶65-77); cationic starches (see: U.S. PatentApplication Publication No. 2004/0204337 A1 and US 2007/0219111 A1);scum dispersants (see: U.S. Patent Application Publication No.2003/0126282 A1, ¶89-90); substantive dyes; hueing dyes (see: U.S.Patent Application Publication No. 2014/0162929 A1); colorants;opacifier; antioxidant; hydrotropes such as toluenesulfonates,cumenesulfonates and naphthalenesulfonates; color speckles; coloredbeads, spheres or extrudates; clay softening agents; anti-bacterialagents. Any one or more of these ingredients is further described indescribed in U.S. Patent Application Publication No. 2010/305020 A1,U.S. Patent Application Publication No. 2003/0139312A1 and U.S. PatentApplication Publication No. 2011/0023240 A1. Additionally oralternatively, the compositions may comprise surfactants, quaternaryammonium compounds, and/or solvent systems. Quaternary ammoniumcompounds may be present in fabric enhancer compositions, such as fabricsofteners, and comprise quaternary ammonium cations that are positivelycharged polyatomic ions of the structure NR₄ ⁺, where R is an alkylgroup or an aryl group.

Composite Articles

Composite articles of the disclosure include at least two layers ofnonwoven webs. The composite articles of the disclosure can have a firstlayer of a first nonwoven web including a first plurality of fibershaving a first diameter, a second layer of a second nonwoven webcomprising a second plurality of fibers having a second diameter, and afirst interface comprising at least a portion of the first nonwoven weband at least a portion of the second nonwoven web, wherein the portionof the first nonwoven web and the portion of the second nonwoven web arefused, and wherein the second diameter is smaller than the firstdiameter. Any nonwoven layer of the composite article can include awater-soluble film laminated thereto.

Composite articles of the disclosure can provide one or more advantages,including but not limited to, increased mechanical strength relative toa nonwoven web identical to a single layer of the composite articlealone, enhanced liquid acquisition function relative to a nonwoven webidentical to a single layer of the composite article alone (e.g., for aliquid acquisition layer of a diaper, or for a spill absorbing wipe),and/or enhanced retention of fluids and/or active compositions relativeto a nonwoven web identical to a single layer of the composite articlealone (e.g., an active lotion for a wet wipe).

The first interface including at least a portion of the first nonwovenweb and at least a portion of the second nonwoven web is the area of thecomposite where the first and second nonwoven webs overlap and the firstplurality of fibers and the second plurality of fibers are intermingled.In general, the portion of the first nonwoven web that forms the firstinterface is an exterior surface of the first nonwoven web. Inembodiments, the first interface comprises 50% or less of the thicknessof the first nonwoven web, 40% or less, 30% or less, 25% or less, 20% orless, 10% or less, 5% or less, 2.5% or less, or 1% or less of thethickness of the first nonwoven web. In embodiments, the first interfacecomprises at least 0.1%, at least 0.5%, at least 1%, or at least 5% ofthe thickness of the first nonwoven. In embodiments, the first interfacecomprises about 0.1% to about 25% of the thicknesses of the firstnonwoven. In general, the portion of the second nonwoven web that formsthe interface is an exterior surface of the second nonwoven web. Inembodiments, the interface comprises 75% or less, 70% or less, 60% orless, 50% or less, 40% or less, 30% or less, 25% or less, 20% or less,or 15% or less of the thickness of the second nonwoven web. Inembodiments, the first interface comprises at least 1%, at least 5%, atleast 10%, at least 20%, at least 25%, at least 30%, or at least 40% ofthe thickness of the second nonwoven web. In embodiments, the firstinterface comprises from about 1% to about 75% of the thickness of thesecond nonwoven web.

As used herein, and unless specified otherwise, two layers of nonwovenwebs are “fused” if at least a portion of the fibers from each web arebonded to fibers from the other web. As described herein, bonding of thefibers includes entangling of the fibers. The two layers of nonwovenwebs can be fused using any suitable method. In embodiments, the portionof the first nonwoven web and the portion of the second nonwoven web arethermally fused, solvent fused, or both. In embodiments, the portion ofthe first nonwoven web and the portion of the second nonwoven web arethermally fused. Thermal fusion can include the use of heat and/orpressure. In embodiments, one or both of two discrete nonwoven webs canbe heated until the fibers are soft and the webs can then be pressedtogether such that when the fibers cool at least a portion of fibersfrom each web are bonded to at least a portion of fibers from the otherweb. In embodiments, one or both of the first and second nonwoven webscan be melt-spun and applied in an inline process such that heated, softfibers are applied directly to a pre-formed nonwoven web after passingthrough the die assembly and fuse to the fibers of the pre-formednonwoven forming a fused interface. In embodiments, the portion of thefirst nonwoven web and the portion of the second nonwoven web aresolvent fused. Solvent fusion can include the application of a bindersolution to one or both of the nonwoven webs followed by contacting thenonwoven webs such that upon drying, at least a portion of fibers fromeach web are bonded to at least a portion of fibers from the other web.Solvent fusion can occur as a discrete process including two discretepre-formed webs or can be an inline process wherein a binder solution isapplied to a pre-formed nonwoven web and a second nonwoven web is formedon the pre-formed nonwoven web in a continuous process. The bindersolution for solvent fusion of the nonwoven web can be any bindersolution described herein for binding. As used herein, and unlessspecified otherwise, a “pre-formed nonwoven web” encompasses nonwovenwebs formed but not bonded and nonwoven webs that have been formed andbonded. As used herein, and unless specified otherwise, a “discretenonwoven web” encompasses nonwoven webs formed by carding or airlayingstaple fibers, or by continuous processes, and the nonwoven webs may ormay not be bonded. In embodiments, the fusing of two nonwoven webs canalso be used to bond one or both of the nonwoven webs.

In embodiments, the first interface is solvent fused and the solvent isselected from the group consisting of water, ethanol, methanol, DMSO,glycerin, and a combination thereof. In embodiments, the first interfaceis solvent fused and the solvent is selected from the group consistingof water, glycerin, and a combination thereof. In embodiments, the firstinterface is solvent fused using a binder solution comprising polyvinylalcohol and water, glycerin, or a combination thereof. In embodiments,the first interface is solvent fused using a binder solution comprisingpolyvinyl alcohol, latex, or a combination thereof and water, glycerin,or a combination thereof.

As used herein, and unless specified otherwise, a first type of fiberhas a diameter that is “smaller than” the diameter of a second type offiber if the average fiber diameter for the first type of fiber is lessthan the average fiber diameter of the second type of fiber. Forexample, the first type of fiber can have an overlapping diameter sizedistribution with the second type of fiber and still have a smallerdiameter as long as the average fiber diameter for the first type offiber is smaller than the average fiber diameter of the second type offiber. In embodiments, the smaller fiber type has an average fiberdiameter that is smaller than the smallest diameter of the diameter sizedistribution of the larger fiber type. A difference in diameter ispresent if the difference can be visualized using projection microscopeimaging as outlined in SO137:2015. In embodiments, the difference indiameter between the smaller fiber type and the larger fiber type can besubmicron, for example, if multiple melt-spun layers are used. Inembodiments, the difference in the diameter between the smaller fibertype and the larger fiber type can be about 1 micron to about 300micron, about 5 micron to about 300 micron, about 5 micron to about 250micron, about 5 micron to about 200 micron, about 10 micron to about 150micron, about 10 micron to about 100 micron, about 10 micron to about 90micron, about 15 micron to about 80 micron, about 15 micron to about 70micron, about 20 micron to about 60 micron, about 20 micron to about 50micron, or about 25 micron to about 45 micron. In embodiments, thedifference in diameter between the smaller fiber type and the largerfiber type can be about 5 micron to about 75 micron. In embodiments, thedifference in diameter between the smaller fiber type and the largerfiber type can be about 20 micron to about 80 micron. Without intendingto be bound by theory, it is believed that providing a composite of twononwoven webs wherein the nonwoven webs are fused and the secondnonwoven web has a fiber diameter that is smaller than the firstnonwoven web advantageously can improve the adsorption/absorption rateand fluid capacity of the composite article, directadsorption/absorption from larger diameter fibers to smaller diameterfibers to move the fluid preferentially; increase the surface to volumeratio of a nonwoven composite article as compared to single diametermaterials resulting in increased loading capacity, and/or improveddispersion and/or total dissolution of the nonwoven composite article ascompared to a nonwoven having a single diameter material. The averagediameters of the fibers in the individual web layers can be anydiameters provided herein. In embodiments, the first plurality of fibersin the first layer of first nonwoven can have a diameter of about 10micron to about 300 micron, about 50 micron to about 300 micron, orabout greater than about 100 micron to about 300 micron. In embodiments,the first plurality of fibers can have an average diameter of greaterthan about 100 micron to about 300 micron. In embodiments wherein anonwoven layer of the nonwoven composite material includes a blend offiber types having different diameters, if the distribution of fiberdiameters is monomodal, the average fiber diameter refers to the averagefiber diameter of the blend. The blend of fiber types can havedistribution of fiber diameters in the nonwoven layer that bimodal orhigher. When a blend of fibers has a bimodal or higher-modal diameterdistribution, a fiber has a smaller diameter than the fibers of saidblend when the fiber has an average fiber diameter less than the averagefor the distribution of the smallest diameter fibers of the blend, and afiber is larger than the fibers of said blend when the fiber has anaverage fiber diameter that is greater than the average for thedistribution of the larger diameter fibers of the blend.

In embodiments, the composite article further comprises a third layer ofa third nonwoven web comprising a third plurality of fibers. Inembodiments wherein the nonwoven composite article includes a thirdlayer of a third nonwoven web, the second layer can be provided betweenthe first layer and the third layer and at least a second portion of thesecond nonwoven web and at least a portion of the third nonwoven web canbe fused, providing a second interface. The second interface includingat least a second portion of the second nonwoven web and at least aportion of the third nonwoven web is the area of the composite where thesecond and third nonwoven webs overlap and the second plurality offibers and the third plurality of fibers are intermingled. In someembodiments, and depending on the thickness of the second layer ofsecond nonwoven web, the first plurality of fibers and the thirdplurality of fibers may become intermingled and/or fused such that thereis no clear delineation between the first interface and the secondinterface. In general, the portion of the second nonwoven web that formsthe second interface is an exterior surface of the second nonwoven webopposite from the exterior surface of the second nonwoven web fused tothe first nonwoven web. In embodiments, the second interface comprises75% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% orless, 25% or less, 20% or less, or 15% or less of the thickness of thesecond nonwoven web. In embodiments, the second interface comprises atleast 1%, at least 5%, at least 10%, at least 20%, at least 25%, atleast 30%, or at least 40% of the thickness of the second nonwoven web.In embodiments, the second interface comprises from about 1% to about75% of the thickness of the second nonwoven web. In embodiments, theportion of the third nonwoven web that forms the second interface is anexterior surface of the third nonwoven web. In embodiments, the secondinterface comprises 50% or less of the thickness of the third nonwovenweb, 40% or less, 30% or less, 25% or less, 20% or less, 10% or less, 5%or less, 2.5% or less, or 1% or less of the thickness of the firstnonwoven web. In embodiments, the second interface comprises at least0.1%, at least 0.5%, at least 1%, or at least 5% of the thickness of thethird nonwoven. In embodiments, the second interface comprises about0.1% to about 25% of the thicknesses of the third nonwoven.

In embodiments, the second portion of the second nonwoven web and theportion of the third nonwoven web are thermally fused, solvent fused, orboth. In embodiments, the second portion of the second nonwoven web andthe portion of the third nonwoven web are thermally fused. Inembodiments, the second portion of the second nonwoven web and theportion of the third nonwoven web are solvent fused.

In embodiments, the second interface is solvent fused and the solvent isselected from the group consisting of water, ethanol, methanol, DMSO,glycerin, and a combination thereof. In embodiments, the secondinterface is solvent fused and the solvent is selected from the groupconsisting of water, glycerin, and a combination thereof. Inembodiments, the second interface is solvent fused using a bindersolution comprising polyvinyl alcohol and water, glycerin, or acombination thereof. In embodiments, the second interface is solventfused using a binder solution comprising polyvinyl alcohol, latex, or acombination thereof and water, glycerin, or a combination thereof.

In embodiments, the first layer of first nonwoven web and the secondlayer of second nonwoven web have different porosities. As used herein,and unless specified otherwise, two nonwoven webs have “differentporosities” when the difference in porosities of the nonwoven web is atleast about 1%. In embodiments, the difference in porosities between twolayers of nonwoven webs in the composite articles can be about 1% toabout 20%. For example, one layer of nonwoven web in a composite articlecan have a porosity of about 80% and a second layer of nonwoven web inthe composite article can have a porosity of about 85%, a 5% differencein porosity. In embodiments, the porosity of the second nonwoven web isless than the porosity of the first nonwoven web. In embodiments, theporosity of the second nonwoven web is the same as the porosity of thefirst nonwoven web. As used herein, and unless specified otherwise, twononwoven webs have the “same porosity” if the difference in porosityvalues between the two nonwoven webs is less than 1%.

In embodiments wherein the composite article comprises a third layer ofa third nonwoven web, the third nonwoven web can have a porosity that isthe same or different from the first nonwoven web. In embodiments, thethird nonwoven web can have the same porosity as the first nonwoven web.In embodiments, the third nonwoven web can have a different porositythan the first nonwoven web. In embodiments, the third nonwoven web canbe less porous than the first nonwoven web. In embodiments, the thirdnonwoven web can have the same porosity as the second nonwoven web. Inembodiments, the third nonwoven web can have a different porosity thanthe second nonwoven web. In embodiments, the third nonwoven web can beless porous than the second nonwoven web. In embodiments, the secondnonwoven web can be less porous than the first nonwoven web and thethird nonwoven web can be less porous than the second nonwoven web. Inembodiments, the nonwoven composite article can have a gradient ofporosity between the layers of nonwoven web, wherein one exteriorsurface of the composite structure can have the largest porosity and theother exterior surface of the composite structure can have the smallestporosity. In embodiments, the composite structure can have a gradient ofporosity between the layers of nonwoven web, wherein the exteriorsurfaces of the composite structure can have the largest porosity andthe middle layer(s) of the composite structure can have the smallestporosity. In embodiments, the composite structure can include a fourthor higher layer of nonwoven webs such that a middle layer(s) can includethe second and third layers of nonwoven webs (for a four-layer compositestructure), or the third layer of nonwoven web (for a five layercomposite structure).

Without intending to be bound by theory, it is believed that when theporosity of the composite structure comprises a gradient, the compositestructure advantageously has enhanced wicking of liquid from the moreporous exterior surface to the less porous exterior surface or lessporous middle layer(s).

The plurality of fibers in any given nonwoven layer of the compositearticle can be any of the fibers disclosed herein, and can be the sameor different. In embodiments, the composition of the fiber formingmaterials in the first plurality, second plurality, and third pluralityof fibers can be the same or different, for example, having anydifference in diameter, length, tenacity, shape, rigidness, elasticity,solubility, melting point, glass transition temperature (T_(g)), fiberforming material, color, or a combination thereof. The following tabledemonstrates contemplated composite articles where the nonwoven layerscan include fibers having three different fiber compositions, whereineach letter “A”, “B”, and “C” refers to a specific fiber composition and“−” means that the contemplated composite article does not include athird layer of nonwoven web. Each of the fiber compositions A, B, and Ccan be (a) a single fiber type including a single fiber formingmaterial, (b) a single fiber type including a blend of fiber formingmaterials, (c) a blend of fiber types, each fiber type including asingle fiber forming material, (d) a blend of fiber types, each fibertype including a blend of fiber forming materials, or (e) a blend offiber types, each fiber type including a single fiber forming materialor a blend of fiber forming materials.

TABLE 1 Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- Com-Com- Com- Com- Com- Com- pos- pos- pos- pos- pos- pos- pos- pos- pos-pos- pos- pos- pos- pos- pos- pos- pos- pos- ite 1 ite 2 ite 3 ite 4 ite5 ite 6 ite 7 ite 8 ite 9 ite 10 ite 11 ite 12 ite 13 ite 14 ite 15 ite16 ite 17 ite 18 1^(st) plurality A A A B B B C C C A A A A A A A A A2^(nd) plurality A B C A B C A B C A A A B B B C C C 3^(rd) plurality —— — — — — — — — A B C A B C A B C Com- Com- Com- Com- Com- Com- Com-Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- pos- pos- pos-pos- pos- pos- pos- pos- pos- pos- pos- pos- pos- pos- pos- pos- pos-pos- ite 19 ite 20 ite 21 ite 22 ite 23 ite 24 ite 25 ite 26 ite 27 ite28 ite 29 ite 30 ite 31 ite 32 ite 33 ite 34 ite 35 ite 36 1^(st)plurality B B B B B B B B B C C C C C C C C C 2^(nd) plurality A A A B BB C C C A A A B B B C C C 3^(rd) plurality A B C A B C A B C A B C A B CA B C

In embodiments, the first plurality of fibers includes water-solublepolyvinyl alcohol (PVOH) fiber forming material. As described herein,the term “the PVOH fiber” is understood to include a fiber comprising ahomopolymer, a copolymer, or a modified copolymer comprising vinylalcohol moieties, for example, 50% or higher of vinyl alcohol moieties,and a fiber comprising such a polymer chemically modified with amodification agent. The chemically modified fiber may comprise no vinylalcohol moieties or less than 50% of vinyl alcohol moieties.

In embodiments, the second plurality of fibers includes water-solublepolyvinyl alcohol fiber forming material. In embodiments, the firstplurality of fibers and the second plurality of fibers includewater-soluble polyvinyl alcohol fiber forming material. In embodimentsincluding a third layer of nonwoven web having a third plurality offibers, the third plurality of fibers can include a water-solublepolyvinyl alcohol fiber forming material. In embodiments, the polyvinylalcohol fiber forming material can be present in one or more fiber typesin the plurality of fibers. The water-soluble polyvinyl alcohol fiberforming materials of any of the first plurality, second plurality, orthird plurality of fibers can be any water-soluble polyvinyl alcoholfiber forming material disclosed herein. In embodiments wherein two ormore of the first plurality of fibers, the second plurality of fibers,and/or the third plurality of fibers include a polyvinyl alcohol fiberforming material, the polyvinyl alcohol can be the same or different ineach plurality, can be the sole fiber forming material or part of blendof fiber forming material in each plurality, and if each pluralityincludes a different polyvinyl alcohol fiber, the difference can be inlength to diameter ratio (L/D), tenacity, shape, rigidness, elasticity,solubility, melting point, glass transition temperature (T_(g)), fiberchemistry, color, or a combination thereof.

In embodiments, the fibers of the first plurality of fibers, the secondplurality of fibers, and/or third plurality of fibers can include afiber forming material other than a polyvinyl alcohol fiber formingmaterial.

In embodiments, the first nonwoven web has a tenacity ratio (MD:CD) ofabout 0.5 to about 1.5. In embodiments, the first nonwoven web has aMD:CD of about 0.8 to about 1.25. In embodiments, the first nonwoven webhas a MD:CD of about 0.9 to about 1.1. In embodiments, the secondnonwoven web has a tenacity ratio (MD:CD) of about 0.5 to about 1.5. Inembodiments, the second nonwoven web has a MD:CD of about 0.8 to about1.25. In embodiments, the second nonwoven web has a MD:CD of about 0.9to about 1.1. In embodiments, the third nonwoven web has a tenacityratio (MD:CD) of about 0.5 to about 1.5. In embodiments, the thirdnonwoven web has a MD:CD of about 0.8 to about 1.25. In embodiments, thethird nonwoven web has a MD:CD of about 0.9 to about 1.1. Inembodiments, the nonwoven composite article has a tenacity ratio (MD:CD)in a range of about 0.5 to about 1.5, about 0.8 to about 1.25, about 0.9to about 1.1, or about 0.95 to about 1.05. In embodiments, the nonwovencomposite article has a MD:CD of about 0.8 to about 1.5. In embodiments,the nonwoven composite article has a MD:CD of about 0.9 to 1.1. TheMD:CD of the nonwoven composite article is related to the MD:CD ratio ofeach individual of layer of nonwoven web present in the compositearticle. Without intending to be bound by theory, it is believed thatthe MD:CD of the composite article cannot be determined by consideringthe MD and CD of each layer of nonwoven web individually, but the MD andCD of the nonwoven composite article must be measured. Without intendingto be bound by theory, it is believed that as the tenacity ratio MD:CDof the nonwoven composite article approaches 1, the durability of thecomposite article is increased, providing superior resistance tobreakdown of the nonwoven when stress is applied to the nonwoven duringuse. Further, without intending to be bound by theory, it is believedthat the MD:CD ratio of a composite article including at least one layerof a melt-spun nonwoven web will have an MD:CD ratio closer to 1:1 thanan identical composite article except including all carded layers.

The basis weights of the nonwoven composite articles of the disclosureare not particularly limiting and can be in a range of about 5 g/m² toabout 150 g/m², about 5 g/m² to about 125 g/m², about 5 g/m² to about100 g/m², about 5 g/m² to about 70 g/m², about 5 g/m² to about 50 g/m²,about 5 g/m² to about 30 g/m². In embodiments, the nonwoven compositearticles of the disclosure can have a basis weight of about 5 g/m² toabout 50 g/m². In embodiments, the nonwoven composite articles of thedisclosure can have a basis weight of about 50 g/m² to about 150 g/m².In embodiments, the first layer of nonwoven web can have a basis weightof about 30 g/m² to about 70 g/m² and the nonwoven composite article canhave a basis weight of about 60 g/m² to about 150 g/m². In embodiments,the first layer of nonwoven web can have a basis weight of about 5 g/m²to about 15 g/m². In embodiments, the first layer of nonwoven web canhave a basis weight of about 5 g/m² to about 15 g/m² and the nonwovencomposite article can have a basis weight in a range of about 15 g/m² toabout 50 g/m². In embodiments, the third layer of nonwoven web can havea basis weight of about 5 g/m² to about 15 g/m². In embodiments, thefirst layer of nonwoven web can have a basis weight of about 5 g/m² toabout 15 g/m² and the third layer of nonwoven web can have a basisweight of about 5 g/m² to about 15 g/m². In embodiments, the secondlayer of nonwoven web can be included in the composite article in about2.5 wt. % to about 10 wt. %, based on the total weight of the compositearticle. In embodiments, the second layer of nonwoven web can beincluded in the composite article in about 2.5 wt. % to about 10 wt. %,based on the total weight of the composite article and the first layerof nonwoven web can be included in the composite article in about 90 wt.% to about 97.5 wt. %, based on the total weight of the compositearticle. In embodiments, the second layer of nonwoven web can beincluded in the composite article in about 2.5 wt. % to about 10 wt. %,based on the total weight of the composite article and the first layerof nonwoven web and the third layer of nonwoven web together areincluded in an about 90 wt. % to about 97.5 wt. %, based on the totalweight of the composite article. In embodiments, the third layer ofnonwoven web can be included in the composite article in about 2.5 wt. %to about 10 wt. %, based on the total weight of the composite articleand the first layer of nonwoven web and second layer of nonwoven webtogether are included in about 45 wt. % to about 48 wt. %, based on thetotal weight of the composite article.

In embodiments, the fiber diameters of the first plurality of fibers canbe substantially uniform. In embodiments, the fiber diameters of thesecond plurality of fibers can be substantially uniform. In embodiments,the fiber diameters of the third plurality of fibers can besubstantially uniform. In embodiments, the fiber diameters of the firstplurality of fibers and third plurality of fibers can be substantiallyuniform. In embodiments, the fiber diameters of each of the firstplurality of fibers, second plurality of fibers, and third plurality offibers can be substantially uniform.

In embodiments, the nonwoven composite article can have an improvedmodulus, tensile strength, elongation, tenacity, or a combinationthereof in the machine direction, cross direction, or both, relative toan identical article comprising only the first layer. In embodiments,the nonwoven composite article can have an improved modulus, tensilestrength, elongation, tenacity, or a combination thereof in the machinedirection, relative to an identical article comprising only the firstlayer. In embodiments, the nonwoven composite article can have animproved modulus, tensile strength, elongation, or a combination thereofin the cross direction, relative to an identical article comprising onlythe first layer. In embodiments, the nonwoven composite article can havean improved modulus, tensile strength, elongation, tenacity or acombination thereof in the machine direction and the cross direction,relative to an identical article comprising only the first layer.

Methods of Preparing Composite Articles

The composite articles can be made using any process known in the artsuitable for combining two or more layers of nonwoven webs such that atleast a portion of the first layer and a portion of the second layer arefused, thereby forming an interface.

In embodiments, the method of forming the nonwoven composite articles ofthe disclosure can include the steps of:

(a) depositing on a first layer including a first nonwoven web, a secondlayer comprising a second nonwoven web under conditions sufficient tofuse at least a portion of the first nonwoven web to at least a portionof the second nonwoven web, thereby forming a first interface; and

(b) optionally, depositing on the second layer comprising the secondnonwoven web, the third layer comprising the third nonwoven web underconditions sufficient to fuse at least a second portion of the secondnonwoven web to at least a portion of the third nonwoven web, therebyforming a second interface.

In embodiments, steps (a) and (b) can be repeated to include additionalnonwoven layers to the composite structure, e.g., a fourth nonwovenlayer, a fifth nonwoven layer, etc.

The conditions sufficient to fuse at least a portion of the firstnonwoven web to at least a portion of the second nonwoven web and/or tofuse at least a second portion of the second nonwoven web to at least aportion of the third nonwoven web can include thermal fusion and/orsolvent fusion, as described herein.

In embodiments of the foregoing methods, the first layer can comprise acarded nonwoven web. In embodiments of the foregoing methods, the thirdlayer can comprise a carded nonwoven web or a melt-spun nonwoven web. Inembodiments of the foregoing methods, the second layer can include amelt-spun nonwoven web or an airlaid nonwoven web. In embodiments, thefirst layer can include a carded nonwoven web, the second layer caninclude a melt-spun nonwoven web, and the third layer can include acarded nonwoven web. In embodiments, the first layer can include acarded nonwoven web, the second layer can include a melt blown nonwovenweb, and the third layer can include a carded nonwoven web. Inembodiments, the second layer can include an airlaid nonwoven web. Inembodiments, the first layer can include a carded nonwoven web, thesecond layer can include an airlaid nonwoven web, and the third layercan include a melt-spun nonwoven web. In embodiments, the first layercan include a carded nonwoven web, the second layer can include anairlaid nonwoven web, and the third layer can include a melt blownnonwoven web. In embodiments, the nonwoven composite article can includefive layers of nonwoven web wherein the first layer can include a cardednonwoven web, the second layer can include an airlaid nonwoven web, thethird layer can include a melt-spun nonwoven web, the fourth layer caninclude an airlaid nonwoven web, and the fifth layer can include acarded nonwoven web. In embodiments, the nonwoven composite article caninclude five layers of nonwoven web wherein the first layer can includea carded nonwoven web, the second layer can include an airlaid nonwovenweb, the third layer can include a melt blown nonwoven web, the fourthlayer can include an airlaid nonwoven web, and the fifth layer caninclude a carded nonwoven web. In embodiments, the second nonwoven webcan include a cellulose fiber forming material.

Flushable Wipes

Flushable wipes of the disclosure can include a nonwoven web of thedisclosure and/or a composite article according to the disclosure.

Flushable wipes can include a plurality of fibers of the disclosure,wherein the plurality of fibers can include water-soluble fibers and,optionally, water-insoluble fibers.

In embodiments wherein the flushable wipe includes a nonwoven webcomprising water-soluble fibers and water-insoluble fibers, the ratio ofwater-insoluble fiber to water-soluble fiber can range from about 1:18to about 4:1, about 1:10 to about 3:1, about 1:5 to about 2:1, or about1:2 to about 2:1, for example about 1:18, 1:16, 1:14, 1:12, 1:10, 1:5,1:3, 1:2, 1:1, 2:1, 3:1, or 4:1.

The flushable wipes of the disclosure can include a cleaning lotion.Flushable wipes of the disclosure generally include fibers having asurface energy that is high enough to allow the fibers to be readily wetby the cleaning lotion during the wetting step of the wipe manufacturingprocess. Thus, in embodiments, at least a portion of at least oneexterior layer of the nonwoven composite article of the flushable wipeincludes a hydrophilic fiber. In embodiments, at least a portion of eachexterior layer of the nonwoven composite article used to prepare theflushable wipe includes a hydrophilic fiber. As used herein, and unlessspecified otherwise, a “hydrophilic fiber” refers to any fiber having asurface thereof that is hydrophilic. A fiber can have a hydrophilicsurface when the fiber includes, for example, a hydrophilic fiberforming material, the fiber is a core-sheath type bicomponent fiberincluding a hydrophilic fiber forming material in the sheath, and/or thefiber has been surface treated to include a hydrophilic material on thesurface thereof. Without intending to be bound by theory, it is believedthat a hydrophilic fiber of a nonwoven can facilitate capillaryaction/wicking of a liquid from a surface of the nonwoven, providingimproved liquid acquisition relative to an identical nonwoven that doesnot include a hydrophilic fiber.

Non-limiting examples of applications for wipes include cleaningsurfaces, cleaning skin, automotive uses, baby care, feminine care, haircleansing, and removing or applying makeup, skin conditioners,ointments, sun-screens, insect repellents, medications, varnishes orindustrial and institutional cleaning.

Lotion Composition

The flushable wipes of the disclosure can comprise a lotion compositionto wet a substrate to facilitate cleaning. In embodiments wherein theflushable wipe is a personal care wipe, the lotion composition may alsoinclude ingredients to soothe, soften, or care for the skin, to improvethe feel of the lotion, to improve the removal of residues from theskin, to provide pleasant scents, and/or to prevent bacterial growth,for example.

Lotion compositions can have a pH at or near about 5.5, close to thephysiological skin pH. Low pH lotion compositions can have a pH at ornear about 3.8 and can be useful in cases where a wipe is being used toremove alkaline residues, such as residues from fecal matter, and helprestore a healthy acidic skin pH of approximately 5 and/or renderirritants from fecal matter non-irritating, as by inactivating fecalenzymes. Low pH lotions may also inhibit microbial growth. Inembodiments wherein the pH of the lotion composition is about 4 or less,the fibers of the first plurality of fibers, second plurality of fibers,and/or third plurality of fibers can include a polyvinyl alcoholcopolymer. The copolymer can be provided as the sole fiber formingmaterial in a fiber of a fiber blend or as one component of a fiberforming material in a fiber including a blend of fiber formingmaterials. In refinements of the foregoing embodiment, the fibers caninclude a blend of polyvinyl alcohol copolymers and homopolymers. Thepolyvinyl alcohol copolymers and homopolymers can be provided in a ratioof about 1:1 to about 4:1. In further refinements of the foregoingembodiments, the polyvinyl alcohol copolymer containing fibers can beblended with non-water-soluble fibers. Either or both of the polyvinylcopolymers and homopolymers may be chemically modified with amodification agent as described herein.

Lotion compositions can comprise a superwetter, a rheology modifier, anemollient and/or an emulsifier. The superwetter can be present in anamount of about 0.01% to 0.2% by weight of the superwetter to the totalweight of the lotion composition. The superwetter can be selected fromthe group consisting of trisiloxanes, polyether dimethicones wherein thepolyether functionality is PEG, PPG, or a mixture thereof, and a mixtureof the foregoing.

The rheology modifier can be present in an amount of about 0.01% to 0.5%by weight of the rheology based on the total weight of the lotioncomposition. The rheology modifier can be selected from the groupconsisting of xanthan gum, modified xanthan gum, and a combinationthereof.

The emollient, if present, may be a thickening emollient. Suitableemollients include, but are not limited to, PEG-10 sunflower oilglycerides, sunflower oil, palm oil, olive oil, emu oil, babassu oil,evening primrose oil, palm kernel oil, cod liver oil, cottonseed oil,jojoba oil, meadowfoam seed oil, sweet almond oil, canola oil, soybeanoil, avocado oil, safflower oil, coconut oil, sesame oil, rice bran oil,grape seen oil, mineral oil, isopropyl stearate, isostearylisononanoate, diethylhexyl fumarate, diisostearyl malate, triisocetylcitrate, stearyl stearate, methyl palmitate, methylheptyl isostearate,petrolatum, lanolin oil and lanolin wax, long chain alcohols like cetylalcohol, stearyl alcohol, behenyl alcohol, isostearyl alcohol, and2-hexyl-decanol, myristyl alcohol, dimethicone fluids of variousmolecular weights and mixtures thereof, PPG-15 stearyl ether (also knownas arlatone E), shea butter, olive butter, sunflower butter, coconutbutter, jojoba butter, cocoa butter, squalene and squalene,isoparaffins, polyethylene glycols of various molecular weights,polypropylene glycols of various molecular weights, or mixtures thereof.

The emulsifier, if present, may be solid at room temperature. Suitableemulsifiers include, but are not limited to, laureth-23, ceteth-2,ceteth-10, ceteth-20, ceteth-21, ceteareth-20, steareth-2, steareth-10,steareth-20, oleth-2, oleth-10, oleth-20, steareth-100, steareth-21,PEG-40 sorbitan peroleate, PEG-8 stearate, PEG-40 stearate, PEG-50stearate, PEG-100 stearate, sorbitan laurate, sorbitan palmitate,sorbitan stearate, sorbitan tristearate, sorbitan oleate, sorbitantrioleate, polysorbate 20, polysorbate 21, polysorbate 40, polysorbate60, polysorbate 61, polysorbate 65, polysorbate 80, polysorbate 81,polysorbate 85, PEG-40 hydrogenated castor oil, citric acid ester,microcrystalline wax, paraffin wax, beeswax, carnauba wax, ozokeritewax, cetyl alcohol, stearyl alcohol, cetearyl alcohol, myristyl alcohol,behenyl alcohol, and mixtures thereof.

In embodiments, the cleaning lotion includes an aqueous emulsionincluding an emollient and an emulsifier.

The cleaning lotion can further comprise humectants including, but notlimited to glycerin, propylene glycol, and phospholipids; fragrancessuch as essential oils and perfumes as described herein; preservatives;enzymes; colorants; oil absorbers; pesticides; fertilizer; activators;acid catalysts; metal catalyst; ion scavengers; detergents;disinfectants; surfactants; bleaches; bleach components; and fabricsofteners. In embodiments, the cleaning lotion includes a fragrance,preservative, enzyme, colorant, oil absorber, pesticide, ion scavenger,detergent, disinfectant, or a combination thereof.

Preservatives prevent the growth of micro-organisms in the liquidlotion, the flushable wipe, and/or the substrate on which the wipe isused. Preservatives can be hydrophobic or hydrophilic. Suitablepreservatives include, but are not limited to parabens, such as methylparabens, propyl parabens, alkyl glycinates, iodine derivatives andcombinations thereof.

The lotion load can be between 150% and 480%. As used herein, “load”refers to combining a nonwoven web or composite article with a lotioncomposition, i.e., a lotion composition is loaded onto or into anonwoven web or composite article, without regard to the method used tocombine the nonwoven web or composite article with the lotioncomposition, i.e., immersion, spraying, kissrolling, etc. A “lotionload” refers to the amount of lotion loaded onto or into a nonwoven webor composite article, and is expressed as weight of the lotion to weightof the dry (unloaded) nonwoven web or composite article, as apercentage. It may be desirable for the flushable wipe to be loaded withlotion to a degree that some of the lotion can be easily transferred toa substrate (e.g., skin or another surface to be cleaned) during use.The transfer may facilitate cleaning, provide a pleasant sensation for auser (such as a smooth skin feeling or coolness from evaporation),and/or allow for the transfer of compounds to provide beneficialfunctions on substrate.

The flushable wipes can be nonwoven webs or composite articles having ahigh density of interstitial spaces between the fibers making up thewipe. In order to maintain enough lotion available on the surface of awipe to transfer to the substrate, much of the interstitial space in thewipe can be filled with lotion. The lotion in the interstitial space maynot be readily available for transfer to a substrate, such that excesslotion can be loaded into the wipe in an amount sufficient to signal tothe user that the lotion is available for transfer to a substrate, forexample, by providing an adequate sense of wetness. Advantageously,nonwoven composite articles used in the flushable wipes can have agradient of porosity as described herein, which can facilitate loadingof the lotion to the wipe.

The flushable wipe can be made by wetting a nonwoven web or compositearticle with at least 1 gram of liquid cleaning lotion per gram of dryfibrous composite. Suitable methods of delivering the cleaning lotion tothe nonwoven web or composite article include but are not limited tosubmersion, spraying, padding, extrusion coating and dip coating. Afterwetting, the wetted composite article can be folded, stacked, cut tolength, and packaged as desired. The flushable wipes are generally ofsufficient dimension to allow for a convenient handling while beingsmall enough to be easily disposed to the sewage system. The wettedcomposite article can be cut or folded to such dimensions during themanufacturing process or can be larger in size and having a means suchas perforations to allow individual wipes to be separated from the web,in a desired size, by a user.

In embodiments, the flushable wipes of the disclosure comprise anonwoven web of the disclosure and a cleaning lotion. In embodiments,the flushable wipes of the disclosure comprise a nonwoven compositearticle of the disclosure and a cleaning lotion. In embodiments, theflushable wipes of the disclosure consist of a nonwoven compositearticle of the disclosure and a cleaning lotion.

Absorbent Articles

The nonwoven webs and nonwoven composite articles of the disclosure canbe used as a liquid acquisition layer for absorbent articles. Theabsorbent articles can include bibs, breast pads, care mats, cleaningpads (e.g., floor cleaning pads), diapers, diaper pants, incontinenceliners, pads, and other articles (e.g., adult incontinence diapers,adult incontinence pads, adult incontinence pants, potty trainingliners, potty training pads, potty training pants, and pet training padse.g., puppy pads), interlabial devices, menstrual pads, panty liners,sanitary napkins, tampons, spill absorbing mats, spill absorbing pads,spill absorbing rolls, wound dressings, and the like. In one aspect, anyof the foregoing articles can be disposable items. The term “disposable”refers to articles that are designed or intended to be discarded after asingle use. That is, disposable articles are not intended to belaundered or otherwise restored or reused, and in embodiments may beincapable of laundering, restoration or reuse.

As used herein, the term “absorbent article” includes articles thatabsorb and contain liquids such as body exudates. The term “absorbentarticle” is intended to include diapers, incontinent articles, sanitarynapkins, and the like. The term “incontinent articles” is intended toinclude pads, undergarments (pads held in place by a suspension systemof some type, such as a belt, or the like), inserts for absorbentarticles, capacity boosters for absorbent articles, briefs, bed pads,and the like, regardless of whether they be worn by adults or otherincontinent persons. At least some of such absorbent articles areintended for the absorption of body liquids, such as menses or blood,vaginal discharges, urine, sweat, breast milk, and fecal matter.

As used herein “diapers” refers to devices that are intended to beplaced against the skin of a wearer to absorb and contain the variousexudates discharged from the body. Diapers are generally worn by infantsand incontinent persons about the lower torso so as to encircle thewaist and legs of the wearer. Examples of diapers include infant oradult diapers and pant-like diapers such as training pants. “Trainingpant”, as used herein, refers to disposable garments having a waistopening and leg openings designed for infant or adult wearers. A pantmay be placed in position on the wearer by inserting the wearer's legsinto the leg openings and sliding the pant into position about awearer's lower torso. A pant may be pre-formed by any suitable techniqueincluding, but not limited to, joining together portions of the articleusing refastenable and/or non-refastenable bonds (e.g., seam, weld,adhesive, cohesive bond, fastener, etc.). A pant may be pre-formedanywhere along the circumference of the article (e.g., side fastened,front waist fastened).

In embodiments, absorbent articles of the disclosure comprise a liquidpervious topsheet, a liquid impervious backsheet joined to the topsheet,and a liquid acquisition layer and an absorbent core between thetopsheet and backsheet. In embodiments wherein the absorbent article isa wearable article (e.g., incontinent articles, sanitary napkins, andthe like), the article can have a wearer facing side and an outer facingside. In general, the liquid pervious topsheet is on the wearer facingside and the liquid impervious backsheet is on the outer facing side ofthe absorbent article. The absorbent core is generally a sheet likestructure and, when provided as a wearable, has a wearer facing side andan outer facing side.

The liquid pervious topsheet can be any liquid pervious topsheet knownin the art. For a wearable article, the topsheet can be fully orpartially elasticized or can be foreshortened to provide a void spacebetween the topsheet and the absorbent core. The liquid imperviousbacksheet can be any liquid impervious backsheet known in the art. Thebacksheet prevents exudates absorbed by the absorbent core and containedwithin the article form contacting any substrate the absorbent articlemay be in contact with. The backsheet can be impervious to liquids andinclude a laminate of a nonwoven and a thin plastic film, such as athermoplastic film. Suitable backsheet films include those manufacturedby Tredegar Industries Inc. of Terre Haute, Ind. and sold under thetrade names X15306, X10962, and X10964. Other suitable backsheetmaterials can include breathable materials that permit vapors to escapefrom the absorbent article, while still preventing liquid from passingthrough the backsheet. Exemplary breathable materials can includematerials such as woven webs, nonwoven webs, and composite materialssuch as manufactured by Mitsui Toatsu Col, of Japan under thedesignation ESPOIR NO and by EXXON Chemical Co., of Bay City, Tex.,under the designation EXXAIRE.

The absorbent core is disposed between the topsheet and the backsheet.The absorbent core can comprise any absorbent material that is capableof absorbing and retaining liquids such as urine and other bodyexudates. The absorbent core can include a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as super absorbent polymer, comminuted wood pulp(air felt), creped cellulose wadding; absorbent foams, absorbentsponges, absorbent gelling materials, or any other known absorbentmaterial or combinations of materials. The absorbent core can includeminor amounts (less than about 10%) of non-liquid absorbent materials,such as adhesives, waxes, oils and the like.

The liquid acquisition layer includes a nonwoven web of the disclosureincluding a plurality of fibers including a water-soluble polyvinylalcohol fiber forming material as described herein. The plurality offibers can include a single fiber type or a blend of fiber types, andthe fibers can include a sole polyvinyl alcohol fiber forming materialor a blend of fiber forming materials including a polyvinyl alcoholfiber forming material. The fibers can comprise fibers chemicallymodified with a modification agent as described herein.

In embodiments, the liquid acquisition layer can be provided between theabsorbent core and the topsheet. In wearable embodiments, the liquidacquisition layer can be provided on the wearer facing side of theabsorbed core. In embodiments, the liquid acquisition layer can beprovided between the absorbent core and the backsheet. In wearableembodiments, the liquid acquisition layer can be provided on the outerfacing side of the absorbent core. In embodiments, the liquidacquisition layer is wrapped around the absorbent core. The liquidacquisition layer can be a single sheet that is wrapped around theabsorbent core or can be provided as two individual layers that arejoined. Without intending to be bound by theory, it is believed that byincluding the liquid acquisition layer between the absorbent core andthe backsheet or on the outer facing side of the absorbent coreadvantageously prevents leakage of the liquid from the absorbent articleby providing additional liquid acquisition material to catch anyoverflow of liquid from the topsheet side and/or wearer facing side.

The liquid acquisition layer can be directly in contact with theabsorbent core, there can include a space between the absorbent core andthe liquid acquisition layer, or there can include an intervening layerbetween the absorbent core and the liquid acquisition layer. Inembodiments, the liquid acquisition layer is in contact with theabsorbent core. In embodiments, the absorbent article includes anintervening layer provided between the acquisition layer and theabsorbent core. In embodiments, the liquid acquisition layer is incontact with the absorbent core on the topsheet side/wearer facing sideand an intervening layer is provided between the acquisition layer andthe absorbent core on the backsheet side/outer facing side. Inembodiments, the liquid acquisition layer is in contact with theabsorbent core on the backsheet side/outer facing side and anintervening layer is provided between the acquisition layer and theabsorbent core on the topsheet side/wearer facing side. The interveninglayer can be, for example, a second liquid pervious layer or liquidacquisition layer included to help facilitate spread of the liquid fromthe point of deposition to cover the full area of the absorbent core.

In embodiments, the absorbent article includes a liquid acquisitionlayer that is a nonwoven web of the disclosure. In embodiments, thewearable absorbent article includes a liquid acquisition layer that is anonwoven web of the disclosure. In embodiments, the absorbent articleincludes a liquid acquisition layer that is a nonwoven composite articleof the disclosure. In embodiments, the wearable absorbent articleincludes a liquid acquisition layer that is a nonwoven composite articleof the disclosure.

Dissolution and Disintegration Test (MSTM-205)

A nonwoven web, water-soluble film, or laminate structure can becharacterized by or tested for Dissolution Time and Disintegration Timeaccording to the MonoSol Test Method 205 (MSTM 205), a method known inthe art. See, for example, U.S. Pat. No. 7,022,656. The descriptionprovided below refers to a nonwoven web, while it is equally applicableto a water-soluble film or laminate structure.

Apparatus and Materials include:

600 mL Beaker,

Magnetic Stirrer (Labline Model No. 1250 or equivalent),

Magnetic Stirring Rod (5 cm),

Thermometer (0 to 100° C.±1° C.),

Template, Stainless Steel (3.8 cm×3.2 cm),

Timer (0-300 seconds, accurate to the nearest second),

Polaroid 35 mm slide Mount (or equivalent),

MonoSol 35 mm Slide Mount Holder (or equivalent), and

Distilled water.

For each nonwoven web to be tested, three test specimens are cut from anonwoven web sample that is a 3.8 cm×3.2 cm specimen. Specimens shouldbe cut from areas of web evenly spaced along the traverse direction ofthe web. Each test specimen is then analyzed using the followingprocedure.

Lock each specimen in a separate 35 mm slide mount.

Fill beaker with 500 mL of distilled water. Measure water temperaturewith thermometer and, if necessary, heat or cool water to maintain thetemperature at the temperature for which dissolution is beingdetermined, e.g., 20° C. (about 68° F.). Mark height of column of water.Place magnetic stirrer on base of holder. Place beaker on magneticstirrer, add magnetic stirring rod to beaker, turn on stirrer, andadjust stir speed until a vortex develops which is approximatelyone-fifth the height of the water column. Mark depth of vortex.

Secure the 35 mm slide mount in the alligator clamp of the 35 mm slidemount holder such that the long end of the slide mount is parallel tothe water surface. The depth adjuster of the holder should be set sothat when dropped, and the end of the clamp will be 0.6 cm below thesurface of the water. One of the short sides of the slide mount shouldbe next to the side of the beaker with the other positioned directlyover the center of the stirring rod such that the nonwoven web surfaceis perpendicular to the flow of the water.

In one motion, drop the secured slide and clamp into the water and startthe timer. Rupture occurs when the sample has become compromised withinthe slide, for example, when a hole is created. Disintegration occurswhen the nonwoven web breaks apart and no sample material is left in theslide. When all visible nonwoven web is released from the slide mount,raise the slide out of the water while continuing to monitor thesolution for undissolved nonwoven web fragments. Dissolution occurs whenall nonwoven web fragments are no longer visible and the solutionbecomes clear. Rupture and dissolution can happen concurrently fornonwoven samples wherein the fibers are prepared from polyvinyl alcoholhaving a low degree of hydrolysis (e.g., about 65-88%). Dissolutiontimes are recorded independently of rupture times when there is a5-second or greater difference between rupture and dissolution.

Thinning time can also be determined using MSTM-205. Thinning of anonwoven web occurs when some of the fibers making up the nonwoven webdissolve, while other fibers remain intact. The thinning of the weboccurs prior to disintegration of the web. Thinning is characterized bya decrease in opacity, or increase in transparency, of the nonwoven web.The change from opaque to increasingly transparent and can be visuallyobserved. During MSTM-205, after the secured slide and clamp have beendropped into the water, the opacity/transparency of the nonwoven web ismonitored. At the time point wherein no change in opacity/transparencyis observed (i.e., the web does not become any less opaque or moretransparent), the time is recorded as the thinning time.

The results should include the following: complete sampleidentification; individual and average disintegration and dissolutiontimes; and water temperature, at which the samples were tested.

Method for Determining Single Fiber Solubility

The solubility of a single fiber can be characterized by the waterbreaking temperature. The fiber breaking temperature can be determinedas follows. A load of 2 mg/dtex is put on a fiber having a fixed lengthof 100 mm. Water temperature starts at 1.5° C. and is then raised by1.5° C. increments every 2 minutes until the fiber breaks. Thetemperature, at which the fiber breaks, is denoted as the water breakingtemperature.

The solubility of a single fiber can also be characterized by thetemperature of complete dissolution. The temperature of completedissolution can be determined as follows. 0.2 g of fibers having a fixedlength of 2 mm are added to 100 mL of water. Water temperature starts at1.5° C. and is then raised by 1.5° C. increments every 2 minutes untilthe fiber completely dissolves. The sample is agitated at eachtemperature. The temperature at which the fiber completely dissolves inless than 30 seconds is denoted as the complete dissolution temperature.

Diameter Test Method

The diameter of a discrete fiber or a fiber within a nonwoven web isdetermined by using a scanning electron microscope (SEM) or an opticalmicroscope and an image analysis software. A magnification of 200 to10,000 times is chosen such that the fibers are suitably enlarged formeasurement. When using the SEM, the samples are sputtered with gold ora palladium compound to avoid electric charging and vibrations of thefiber in the electron beam. A manual procedure for determining the fiberdiameters is used from the image (on monitor screen) taken with the SEMor the optical microscope. Using a mouse and a cursor tool, the edge ofa randomly selected fiber is sought and then measured across its width(i.e., perpendicular to the fiber direction at that point) to the otheredge of the fiber. A scaled and calibrated image analysis tool providesthe scaling to get an actual reading in microns. For fibers within anonwoven web, several fibers are randomly selected across the sample ofnonwoven web using the SEM or the optical microscope. At least twoportions of the nonwoven web material are cut and tested in this manner.Altogether at least 100 such measurements are made and then all data arerecorded for statistical analysis. The recorded data are used tocalculate average (mean) of the fibers, standard deviation of thefibers, and median fiber diameters.

Tensile Strength, Modulus, and Elongation Test

A nonwoven web, water-soluble film, or laminate structure characterizedby or to be tested for tensile strength according to the TensileStrength (TS) Test, modulus (or tensile stress) according to the Modulus(MOD) Test, and elongation according to the Elongation Test is analyzedas follows. The description provided below refers to a nonwoven web,while it is equally applicable to a water-soluble film or laminatestructure. The procedure includes the determination of tensile strengthand the determination of modulus at 10% elongation according to ASTM D882 (“Standard Test Method for Tensile Properties of Thin PlasticSheeting”) or equivalent. An INSTRON tensile testing apparatus (Model5544 Tensile Tester or equivalent) is used for the collection ofnonwoven web data. A minimum of three test specimens, each cut withreliable cutting tools to ensure dimensional stability andreproducibility, are tested in the machine direction (MD) (whereapplicable) for each measurement. Tests are conducted in the standardlaboratory atmosphere of 23±2.0° C. and 35±5% relative humidity. Fortensile strength or modulus determination, 1″-wide (2.54 cm) samples ofa nonwoven web are prepared. The sample is then transferred to theINSTRON tensile testing machine to proceed with testing while minimizingexposure in the 35% relative humidity environment. The tensile testingmachine is prepared according to manufacturer instructions, equippedwith a 500 N load cell, and calibrated. The correct grips and faces arefitted (INSTRON grips having model number 2702-032 faces, which arerubber coated and 25 mm wide, or equivalent). The samples are mountedinto the tensile testing machine and analyzed to determine the 100%modulus (i.e., stress required to achieve 100% film elongation), tensilestrength (i.e., stress required to break film), and elongation % (samplelength at break relative to the initial sample length). In general, thehigher the elongation % for a sample, the better the processabilitycharacteristics for the nonwoven web (e.g., increased formability intopackets or pouches).

Determination of Basis Weight

Basis weight is determined according to ASTM D3776/D3776M-09a (2017).Briefly, a nonwoven specimen having an area of at least 130 cm² or anumber of smaller die cut specimens taken from different locations inthe sample and having a total area of at least 130 cm² are cut. Thespecimen(s) are weighed to determine mass on a top loading analyticalbalance with a resolution of ±0.001 g. The balance is protected from airdrafts and other disturbances using a draft shield. Specimens of fabricmay be weighed together. The mass is calculated in ounces per squareyard, ounces per linear yard, linear yards per pound, or grams persquare meter to three significant figures.

Determination of Moisture Vapor Transmission Rate

Moisture Vapor Transmission Rate (MVTR) is determined according toMSTM-136. The MVTR defines how much moisture per day moves through asample. The description provided below refers to a nonwoven web, whileit is equally applicable to a water-soluble film or laminate structure.

Apparatus and Materials include:

Permatran-W Model 3/34 (or equivalent),

Compressed Gas Cylinder of Nitrogen (99.7% or above),

Regulator-Tee (part number 027-343),

Main Line Supply regulator,

HPLC Grade Water (or equivalent),

10 cc Syringe with Luerlok Tip (part number 800-020),

Powder-free gloves,

High vacuum grease (part number 930-022),

(2) Test Cells,

Cutting template,

Cutting board,

Razor blade with handle, and

Cut-resistant glove.

Preparation of the Permatran W-Model 3/34: Make sure nitrogen pressurelevel is above 300 psi, the pressure on the carrier gas regulator-teereads 29 psi (must not exceed 32 psi), and the main line supplyregulator pressure is set to 35 psi. Open the door on the instrumentpanel to access humidifier to check the water level. If water level islow, fill a syringe with HPLC-grade water and insert the leur fitting onthe syringe into the “fill Port” for the reservoir. Open the “FillValve” by turning it 2-3 turns counterclockwise then push in the plungeron the syringe to force the water into the reservoir. Close the ‘FillValve” and remove syringe. The water level should not exceed a linemarked adjacent to reservoir.

Preparation and Testing of Samples: For each nonwoven web to be tested,take the sample web and lay it flat on the cutting board. Place thetemplate on top of the web and use the razor blade with a handle to cutout the sample. Make sure cut-resistant glove is worn when cutting thesample out. Set the sample aside. Grease around the sealing surfaces ofthe test cell's top piece with high vacuum grease. Mount the film sampleon top of the test cell's top piece. Orientation may be important. If ahomogeneous material, orientation is not critical. If a multi-layeredand laminated material, place the multilayered film or laminate withbarrier coating or laminate up, towards the top of the cell. Forexample, a one-side, wax coated PVOH web should be mounted with the waxside up, placing the wax towards the carrier gas (Nitrogen). Place thetest cell's top piece on top of the test cell's bottom piece. Make surethe test cell is clamped together with a good seal. Press the cellload/unload button to open cell tray. Grasp the test cell by the frontand back edges and lower it straight down. Close the cell traycompletely by gently pushing straight towards panel. Press the cellload/unload button to clamp the cell while a click can be heard. Repeatfor second sample.

After the samples are loaded and the instrument is ready, the testparameters must be set. There are two types of test parameters, cellparameters and instrument parameters. Cell parameters are specific toeach cell while instrument parameters are common for all cells. Touchthe “Test Button” on the screen. Under “Auto Test” select “Tab A”. Touch“Cell Tab”. Fill out the following by touching each bubble: ID, Area(cm²), Thickness (mil). Note: Area of template is 50 cm². Repeat for“Tab B”. Touch “Instrument Tab”. Fill out the following by touching eachbubble: Cell Temp (° C.) and Test Gas RH (%). Make sure 100% RH is setto off. Cell temperature can be set to a minimum of 10° C. to maximum of40° C. Test Gas RH can be set to minimum 5% to 90%. If 100% RH isneeded, it requires a different method. Repeat for “Tab B”. Once thetest parameters are set, select “Start Selected” or “Start All”depending on sample number. Note: The indicator light for each cell onfront panel will be green indicating the start of test.

Surface Resistivity Measurements

Surface resistivity of nonwoven webs and films can be measured accordingto ASTM D257.

Softness Rating

The hand feel of a nonwoven web or pouch of the disclosure is related tothe softness of the sample and can be evaluated using relative testingmethods. A tester carrying out the softness evaluation uses clean handsto feel the samples in whatever manner or method the individual chose,to determine a softness rating for the nonwoven webs and articles of thedisclosure as compared to a control material comprising a nonwoven webconsisting of fibers consisting of polyvinyl alcohol copolymers having adegree of hydrolysis of 88%, the fibers having a 2.2 dtex/51 mm cut,having a softness rating of 1 (softest) and a control materialcomprising a nonwoven web consisting of fibers consisting of 75%polyvinyl alcohol copolymers having a degree of hydrolysis of 88%, thefibers having a 2.2/51 mm cut, and 25% of 22 dtex/38 mm PET fiber,having a softness rating of 5 (roughest/coarsest). The hand panel is ablind study so that the raters are not swayed by their perception ofsample names. Samples were rated from 1 to 5.

Flushability Test

The ability of the nonwoven webs and/or laminates of the disclosure tobe flushed in a septic or municipal sewage treatment system can bedetermined according to a modified INDA/EDANA—Criteria for Recognitionas a Flushable Product, as provided below. The below test referencesnonwoven web samples; however, it will be understood that the method canalso be used for laminate structures.

Equipment and materials include:

Rocking digital platform shaker,

Two clear, plastic, 12×5×3.9 inches containers,

Two sieves (12.5 mm apertures),

Dried nonwoven web samples, and

A 100° C. oven.

Parameters include:

Rocking platform set to 18 RPM and 11° tilt period,

1 L tap water per container, and

30 min testing period.

Testing Procedure:

-   -   1. Place two containers on rocking platform. This method tests        two samples at a time.    -   2. Measure 1 L of tap water in beaker and pour into one plastic        container. Repeat for other container. Make sure tap water in        containers is at 15° C.±1° C. before starting test.    -   3. Record weight of the initial dried test sample (initial        sample mass (g)) and weight of sieves (initial sieve mass (g))        and record independently.    -   4. Set appropriate parameters on digital rocking platform.    -   5. Place each test sample in their corresponding container and        immediately start the agitation process (rocking of the        platform),    -   6. Once the process is complete (after 30 minutes), take each        container and pour through their corresponding sieves. Pouring        at a height of 10 cm above sieve plate.    -   7. Rinse container into sieve to ensure all of the remaining        test sample was removed.    -   8. Place sieve in 100° C. oven for 45 minutes to ensure all        water evaporates.    -   9. Record weight of sieve and remaining test sample together        (total final mass (g)).    -   10. Calculate the total retained sample mass (final sample mass        (g)):

Final sample mass(g)=total final mass(g)−initial sieve mass(g)

-   -   11. Calculate the percent (%) disintegration:

% Disintegration=[1−(final sample mass(g)/initial sample mass(g))]×100

-   -   12. Make sure sieves are cleaned, dried, and re-weighed before        starting next test.    -   13. Repeat test until replicate of N=3 is complete for each        specific test sample.

A sample is sufficiently flushable to be disposed of by flushing in aseptic or municipal sewage treatment system when the sample has apercent disintegration equal to or greater than of at least 20%. Inembodiments, the nonwoven webs, laminates, and pouches of the disclosurecan have a percent disintegration of at least 20%, at least 30%, atleast 35%, at least 40%, at least 45%, at least 50%, at least 55%, atleast 60%, at least 65%, at least 70%, at least 75%, at least 80%, atleast 85%, at least 90%, or at least 95% as measured by the FlushabilityTest.

Liquid Release Test

A wire frame cage is used for a sample, such as a water-soluble pouch,in the Liquid Release Test described herein. An apparatus for performingthe Liquid Release Test includes a beaker resting on a stand, the standholding a rod for lowering the cage into the beaker, and the rod beingfixable by a collar with a set screw.

A water-soluble nonwoven web, film, and/or pouch characterized by or tobe tested for delayed solubility according to the Liquid Release Test isanalyzed as follows using the following materials:

2 L beaker and 1.2 liters of deionized (DI) water;

Water-soluble pouch to be tested (the pouch is pre-conditioned for twoweeks at 38° C.; for results to be comparative, all nonwoven webs testedshould have the same basis weight and all films tested should have thesame thickness, for example, 88 μm or 76 μm);

Thermometer;

Wire cage; and

Timer.

Before running the experiment, ensure that enough deionized water isavailable to repeat the experiment five times, and ensure that the wirecage and beaker are clean and dry.

The wire frame cage is a plastic coated wire cage (4″×3.5″×2.5″) with nosharp edges, or equivalent. The gauge of the wire should be about 1.25mm and the wire should have openings the size of 0.5 inch (1.27 cm)squares.

To set up for the test, carefully place the water-soluble pouch in thecage while not scratching the pouch on the cage and allowing free spacefor the pouch to move. Do not bind the pouch tightly with the wire cage,while still ensuring it is secure and will not come out of the cage. Theorientation of the pouch in the cage should be such that the naturalbuoyancy of the pouch, if any, is allowed (i.e., the side of the pouchthat will float to the top should be placed towards the top). If thepouch is symmetrical, the orientation of the pouch generally will notmatter.

Next, fill the 2 L beaker with 1200 milliliters of 20° C. deionizedwater.

Next, lower the wire frame cage with the enclosed pouch into the water.Ensure that the cage is 1 inch (2.54 cm) from the bottom of the beaker.Be sure to fully submerge the pouch on all sides. Ensure that the cageis stable and will not move and start a timer as soon as the pouch islowered into the water. The position of the cage with respect to thewater in the beaker can be adjusted and maintained by any suitablemeans, for example, by using a clamp fixed above the beaker, and a rodattached to the top of the cage. The clamp can engage the rod to fix theposition of the cage, and tension on the clamp can be lowered in orderto lower the cage into the water. Other means of frictional engagementcan be used in the alternative to a clamp, for example, a collar with aset screw.

Liquid content release is defined as the first visual evidence of theliquid leaving the submerged pouch.

Determination of the Degree of Hydrolysis of a Fiber

Titration Method. The degree of hydrolysis of a polymer in a fiber canbe determined using titration. In particular, a known amount ofpolyvinyl alcohol fibers are dissolved in 200 mL of deionized water byagitation and heating the mixture at a temperature higher than 70° C.Once all of the PVOH polymer has dissolved, the solution is cooled toroom temperature. Once the solution has cooled, 4-5 drops ofphenolphthalein indicator solution are added to the PVOH solution, alongwith 20.0 mL of 0.5N NaOH solution. The solution is mixed and left atroom temperature for a minimum of 2 hours. After this time, 20.0 mL of0.5N sulfuric acid are added to the solution and mixed. The solution istitrated with 0.1N NaOH solution until the endpoint, which is taken asthe point at which the solution turns faint pink and maintains thiscolor without returning to a colorless solution for a minimum of 30seconds. Using the measurements obtained in the aforementionedprocedure, the DH of the PVOH polymer is determined via the followingcalculations

${{A_{1} = \frac{\left( {V_{sample} - V_{blank}} \right) \times N \times {0.0}6005}{Wt_{sample} \times \frac{P}{100}}}A_{2}} = \frac{4{4.0}5 \times A_{1}}{{6{0.0}5} - \left( {{0.4}2 \times A_{1}} \right)}$DH = 100 − A₂

where:A1: residual acetate groups (wt %)A2: residual acetate groups (mole %)DH: degree of hydrolysis (mole %)Vsample: volume of 0.1N NaOH solution added during titration of sample(mL)Vblank: volume of 0.1N NaOH solution added during titration of blank(mL)N: certified concentration of standardized 0.1N NaOH solution used intitration step Wtsample: sample mass (g)P: purity of PVOH sample=100−(volatile matter (wt %)+sodium acetate (wt%)).

FTIR Method. FTIR can be used to determine if a modification to theouter portion of a fiber surface has occurred via attenuated totalreflectance (ATR). The depth of the fiber which this method measures isdependent on the specific ATR apparatus, in particular, the crystalused, and can range from less than 1 to several microns. Determinationof the existence of a specific modification via ATR is dependent on thechemical structure of the modifying agent, and therefore on the chemicalstructure of the resulting fiber. For example, if a fiber were to bemodified such that it would result in the presence of nitro functionalgroups in the chemical structure of the fiber, this could be detectedvia ATR. Nitro functional groups exhibit strong IR absorbance in theregion of 1515-1560 cm⁻¹. A relative increase in absorbance signal inthis region, when compared to a non-modified fiber, is indicative ofsuccessful modification of the fiber given the fiber has been properlywashed of reactants, solvents, and/or activating agents from themodification process that may contain nitro and/or other functionalgroups that potentially absorb in the same region. In the same way,determination of modified fibers containing other functional groups withknown absorbance values can be detected, given that such fibers havebeen properly washed of reactants, solvents, and/or activating agentsfrom the modification process that potentially absorb in the sameregion. A Thermo Scientific Nicolet iS10 FTIR Spectrometer using aThermo Scientific Smart iTX ATR accessory equipped with a diamondcrystal or equivalent can be used to characterize samples.

DSC Method (MSTM-122). A fiber, a nonwoven web, water-soluble film, orlaminate structure can be characterized by or tested by differentialscanning calorimetry (DSC). This method is used to determine the meltingpoint, glass transition, crystallization, and heat of fusion events invarious polymer samples (e.g., polyvinyl alcohol samples). An Auto Q20DSC or equivalent can be used to characterize the samples.

Test Specimen

The polymer sample should be between 0.00300 g and 0.01200 g (3.00mg-12.00 mg) unless otherwise stated. Sample size is dependent on thematerial tested, and must cover the bottom of the pan. The sample mustfit inside the sealed pan without puncturing or deforming the pan.

Gradient Test Method. A gradient in the degree of modification of afiber can be determined and quantified using cross-section X-rayphotoelectron spectroscopy (XPS), depth XPS, NMR techniques (such as,solid state NMR), ultraviolet photoelectron spectrometry (UPS),environmental SCM, Auger electron spectroscopy (AES or SAM), orelemental scanning electron microscopy (SEM). The shift in bondingenergy of the modification from an —OH group or a —COMe group from thepolyvinyl alcohol or polyvinyl acetate prior to the modification wouldresult in a change in the spectrum of the methods. It is noted that thechemical shifts will differ based on the type of modification that isdone to the fiber.

For XPS analysis, the depth of the fiber which this method measures isdependent on the specific ion beam used during the XPS analysis fordepth profiling to determine changes in degree of modification as afunction of cross section. By taking the ratio of the deconvoluted peaksat 287.6 eV and 288.8 eV, representing the carboxyl and carbonyl groupsof acetate groups for non-fully hydrolyzed PVOH, combined with those of286.5 eV and 532.8 eV, corresponding to the hydroxyl groups of PVOH, tothe peaks that correspond with particular modification that is made tothe PVOH, one can use the equation obtained by plotting the same ratiosfor PVOH resins against the known degree of modification (if any) of thestarting PVOH to determine the degree of modification of the unknownsample. This method can be repeated between ion beam sputtering stagesto gain a complete depth profile and change of degree of modificationacross the cross-section of the PVOH fibers. XPS methods are describedin Gilbert et al “Depth-profiling X-ray photoelectron spectroscopy (XPS)analysis of interlayer diffusion in polyelectrolyte multilayers” PNAS,vol. 110, no. 17, 6651-6656 (2013)(https://www.pnas.org/content/pnas/1/10/1/6651.full.pdf), and EuropeanPolymer Journal 126 (2020) 109544, the entirety of which are herebyincorporated by reference.

AES methods are described in ASTM E984-12, the entirety of which ishereby incorporated by reference.

One or more optional features that can be used individually or incombination are described in the following paragraphs. Optionally, thefiber to be treated is a polyvinyl acetate fiber. Optionally, the fiberto be treated is a polyvinyl alcohol fiber. Optionally, the fiber to betreated is a polyvinyl alcohol fiber comprising a polyvinyl alcoholcopolymer having a degree of hydrolysis in a range of 79-99%.Optionally, the fiber to be treated is a polyvinyl alcohol fibercomprising a polyvinyl alcohol copolymer having a degree of hydrolysisin a range of 88%-96%. Optionally, the fiber to be treated is apolyvinyl alcohol fiber comprising a polyvinyl alcohol copolymer havinga degree of hydrolysis of 88%, 92%, or 96%. Optionally, the fiber to betreated is a polyvinyl alcohol fiber comprising a polyvinyl alcoholhomopolymer or copolymer. Optionally, the fiber to be treated is apolyvinyl alcohol fiber comprising an anionically modified copolymer.Optionally, the fiber to be treated is a polyvinyl alcohol fibercomprising a polyvinyl alcohol (PVOH) copolymer and an anionicallymodified PVOH copolymer. An example of a PVOH copolymer is a copolymerof vinyl acetate and vinyl alcohol.

Optionally, the modification agent comprises a maleic anhydride.Optionally, the solvent for the modification agent comprises methanol.Optionally, the solvent for the modification agent comprises methanoland water. Optionally, the method further comprises an activator,wherein the activator comprises sodium hydroxide.

Optionally, the admixing of the fiber to be treated, the modificationagent, and the solvent comprises immersing the fiber in the solvent withthe modification agent. Optionally, the admixing comprises heating themixture of the fiber, the modification agent, and the solvent.Optionally, the admixing comprises heating the mixture of the fiber, themodification agent, and the solvent to a temperature of about 65° C. toabout 75° C. Optionally, the admixing comprises heating the mixture ofthe fiber, the modification agent, and the solvent for up to about threeto about seven hours.

Optionally, the fiber to be treated can be contacted with themodification agent to increase the degree of modification of a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety of the fiber in a region of the fiber comprising at least thesurface of the fiber. Optionally, the contacting can be by immersion.Optionally, the contacting can be by dip-coating. Optionally, thecontacting can be by spraying. Optionally, the contacting can be bybrushing. Optionally, the contacting can be by rolling.

The following paragraphs describe further aspects of the disclosure.

1. A method of treating a fiber, comprising:

contacting a surface of a fiber comprising a polymer comprising at leastone of a vinyl acetate moiety or a vinyl alcohol moiety with amodification agent to chemically modify at least a portion of thepolymer with the modification agent in a region of the fiber comprisingat least the surface of the fiber so as to form a modified fiber.

2. The method according to clause 1, further comprising adding a solventfor the modification agent.

3. The method according to clause 2, wherein contacting a surface of thefiber with the modification agent comprises admixing the fibercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety, the modification agent, and the solvent.

4. The method according to any of clauses 2 or 3, wherein the fiber isnot soluble in the solvent for a duration of contact of the fiber withthe solvent.

5. The method according to any of clauses 2-4, further comprisingheating the fiber in the solvent prior to contacting a surface of thefiber with the modification agent.

6. The method according to any of clauses 2-4, further comprisingheating the fiber, the modification agent, and the solvent.

7. The method according to any of clauses 1-6, wherein the surface ofthe fiber is contacted with the modification agent for a period of timeup to about 48 hours.

8. The method according to any of clauses 1-7, wherein the surface ofthe fiber is contacted with the modification agent at a temperature in arange of from about 10° C. to about 100° C.

9. The method according to any of clauses 1-8, wherein the polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety has a degree of hydrolysis greater than about 79% and less thanabout 99.9% prior to contacting a surface of the fiber with themodification agent.

10. The method according to any of clauses 1-9, wherein contacting asurface of the fiber with the modification agent is performed underconditions sufficient to provide a controlled amount of chemicalmodification to the polymer comprising at least one of a vinyl acetatemoiety or a vinyl alcohol moiety and/or controlled increase of chemicalmodification to the polymer comprising at least one of a vinyl acetatemoiety or a vinyl alcohol moiety.

11. The method according to any of clauses 1-10, wherein the chemicalmodification of at least a portion of the polymer with the modificationagent comprises one or more of the following: esterification, amidation,amination, carboxylation, nitration, acyloin condensation, allylation,acetylation, imidization, halogenation, sulfonation, alkylation,enolization, nitrosation, and silane coupling.

12. The method according to any of clauses 1-11, further comprisingadmixing an activator with the fiber and the modification agent, theactivator comprising an acid, a base, an aziridine, a free radicalinitiator, or a combination thereof.

13. The method according to any of clauses 1-12, wherein themodification agent comprises an anhydride, a carboxylic acid, analcohol, an ester, an ether, a sulfonic acid, a sulfonate, a clickchemistry reagent, an amide, an amine, a lactam, a nitrile, a ketone, anallyl containing compound, an acetyl containing compound, a halogen, analkyl containing compound, an imide, an acetal containing compound, anenolate, a nitro containing compound, a silane, an aziridine, anisocyanate, or any combination thereof.

14. The method according to any of clauses 1, wherein the modified fibercomprises a monocarboxylic acid, a dicarboxylic acid, a sulfonic acid, asulfonate, a click chemistry reagent, an amide, an amine, a nitrile, aketone, an ester, an allyl, an acetyl, a halogen, an alkyl, an imide, anacetal, an enolate, a nitro, a silane, or any combination thereof.

15. The method according to clause 13, wherein the sulfonate comprisesaminopropyl sulfonate.

16. The method according to clause 13, wherein the lactam comprises apyrrolidone or a caprolactam.

17. The method according to clause 13, wherein the sulfonic acidcomprise 2-acrylamido-2-methylpropanesulfonic acid.

18. The method according to clause 13, wherein the monocarboxylic acidor the dicarboxylic acid comprises acetic acid, maleic acid, monoalkylmaleate, dialkyl maleate, fumaric acid, monoalkyl fumarate, dialkylfumarate, itaconic acid, monoalkyl itaconate, dialkyl itaconate,citraconic acid, monoalkyl citraconate, dialkyl citraconate, mesaconicacid, monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid,monoalkyl glutaconate, dialkyl glutaconate, alkyl (alkyl)acrylates,alkali metal salts of the foregoing, hydrolyzed alkali metal saltsthereof, esters thereof, or any combination thereof.

19. The method according to any of clauses 1-18, wherein themodification agent comprises an anhydride.

20. The method according to clause 19, wherein the anhydride is anorganic acid anhydride and the organic acid anhydride comprises aceticanhydride, propionic anhydride, isobutyric anhydride, maleic anhydride,phthalic anhydride, glutaric anhydride, itaconic anhydride, citraconicanhydride, glutaconic anhydride, or any combination thereof.

21. The method according to clause 19, wherein the anhydride comprisesmaleic anhydride.

22. The method according to clause 2, wherein the modification agent isprovided in an amount of about 0.2% to about 75% (w/w) based on theweight of the solvent.

23. The method according to clause 2, wherein the solvent comprises apolar solvent.

24. The method according to clause 2, wherein the solvent comprises oneor more solvents selected from the group consisting of methanol,ethanol, n-propanol, isopropanol, tetrahydrofuran, dichloromethane,acetone, N-methylpyrrolidone, acetonitrile, N,N-dimethylformamide,dimethyl sulfoxide, formic acid, water, and any combination thereof.

25. The method according to clause 2, wherein the solvent comprises anonpolar solvent.

26. The method according to clause 2, wherein the solvent comprises analcohol that is a liquid under admixing conditions.

27. The method according to clause 2, wherein the solvent comprises amixture of a first solvent and a second solvent.

28. The method according to clause 27, wherein the first solventcomprises water and the second solvent comprises an alcohol.

29. The method according to clause 28, wherein the second solventcomprises methanol, ethanol, n-propanol, isopropanol, or any combinationthereof.

30. The method according to any of clauses 1-29, wherein contacting asurface of the fiber with the modification agent is performed underconditions sufficient to provide an anionically modified polymer.

31. The method according to clause 30, wherein the anionically modifiedpolymer comprises a carboxylate, a sulfonate, or a combination thereof.

32. The method according to any of clauses 1-31, wherein the polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety comprises a polyvinyl alcohol homopolymer, a polyvinyl acetatehomopolymer, a polyvinyl alcohol copolymer, or combinations thereof.

33. The method according to clause 32, wherein the polyvinyl alcoholcopolymer is a copolymer of vinyl acetate and vinyl alcohol.

34. The method according to any of clauses 1-33, wherein the fiberfurther comprises an additional polymer.

35. The method according to clause 34, wherein the additional polymer isselected from the group consisting of a polyvinyl alcohol, a polyvinylacetate, a polyacrylate, a water-soluble acrylate copolymer, a polyvinylpyrrolidone, a polyethylenimine, a pullulan, a guar gum, a gum Acacia, axanthan gum, a carrageenan, a starch, a modified starch, a polyalkyleneoxide, a polyacrylamide, a polyacrylic acid, a cellulose, a celluloseether, a cellulose ester, a cellulose amide, a polycarboxylic acid, apolyaminoacid, a polyamide, a gelatin, a dextrin, copolymers of theforegoing, and any combination of any of the foregoing additionalpolymers or copolymers.

36. The method according to any of clauses 1-35, wherein contacting asurface of the fiber with the modification agent is performed underconditions sufficient to provide a fiber having a transversecross-section having a core-sheath structure including a core and asheath, wherein the polymer of the core has a first amount of chemicalmodification and the polymer of the sheath has a second amount ofchemical modification greater than the first amount.

37. The method according to any of clauses 1-36, wherein contacting asurface of the fiber with the modification agent is performed underconditions sufficient to provide a fiber having a transversecross-section characterized by an increasing gradient in the amount ofchemical modification of the polymer from an interior region to thesurface region.

38. The method according to any of clauses 1-37, wherein contacting asurface of the fiber with the modification agent is performed underconditions sufficient to provide a fiber having a transversecross-section characterized by the polymer having an equal amount ofchemical modification across the transverse cross-section.

39. The method according to any of clauses 1-38, wherein the fiber iswater-soluble or not water soluble prior to contacting a surface of thefiber with the modification agent.

40. The method according to any of clauses 1-39, wherein the modifiedfiber is water-soluble.

41. The method according to any of clauses 1-40, wherein, prior tocontacting a surface of the fiber with the modification agent, the fiberhas a first complete dissolution temperature and the modified fiber hasa second complete dissolution temperature different from the firstcomplete dissolution temperature.

42. The method according to clause 41, wherein the first completedissolution temperature is greater than the second complete dissolutiontemperature.

43. The method according to clause 41, wherein the first completedissolution temperature is lower than the second complete dissolutiontemperature.

44. The method according to any of clauses 1-43, wherein contacting asurface of the fiber with the modification agent is performed by one ormore of the following: immersion, spraying, transfer coating, wicking,foaming, brushing, rolling, humidification, vapor deposition, printing,or any combination thereof.

45. The method according to clause 44, wherein contacting a surface ofthe fiber with the modification agent and a solvent is performed afterformation of the fiber as part of a continuous inline process.

46. The method according to any of clauses 1-45, wherein the fiber is inmotion during the contacting of a surface of the fiber with themodification agent and a solvent.

47. The method according to any of clauses 1-46, wherein contacting asurface of the fiber with the modification agent is performed in abatchwise process.

48. The method according to any of clauses 1-47, wherein the fibercomprises staple fiber, staple yarn, fiber fill, needle punch fabrics,bonding fibers, or any combination thereof.

49. The method according to any of clauses 1-48, further comprisingwashing and drying the fiber after contacting a surface of the fiberwith the modification agent.

50. The method according to clause 49, wherein washing the fibercomprises rinsing the fiber with a non-solvent.

51. The method according to clause 49, wherein drying the fibercomprises one or more of the following: air jet drying, agitating,vortexing, centrifuging, or any combination thereof.

52. A method of treating a nonwoven web comprising a plurality offibers, each fiber of the plurality of fibers comprising a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety, the method comprising:

contacting at least a portion of the nonwoven web with a modificationagent to chemically modify the polymer in a first region of each fiberwith the modification agent so as to provide a modified nonwoven web.

53. The method according to clause 52, further comprising adding asolvent for the modification agent.

54. The method according to clause 52 or 53, wherein contacting at leasta portion of the nonwoven web with the modification agent is performedby one or more of the following: immersion, spraying, transfer coating,wicking, foaming, brushing, rolling, humidification, vapor deposition,printing, or any combination thereof.

55. The method according to any of clauses 52-54, further comprisingconcurrently bonding the plurality of fibers into the nonwoven web whilecontacting the at least a portion of the nonwoven web with themodification agent.

56. The method according to clause 55, wherein bonding the plurality offibers comprises chemical bonding the plurality of fibers.

57. The method according to clause 55, wherein bonding the plurality offibers comprises using a heat activated catalysis.

58. The method according to any of clauses 52-57, wherein the polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety comprises a polyvinyl alcohol homopolymer, a polyvinyl acetatehomopolymer, a polyvinyl alcohol copolymer, or any combination thereof.

59. The method according to clause 58, wherein the polyvinyl alcoholcopolymer is a copolymer of vinyl acetate and vinyl alcohol.

60. The method according to clause 58, wherein the polyvinyl alcoholcopolymer comprises an anionically modified copolymer.

61. The method according to clause 58, wherein the anionically modifiedcopolymer comprises a carboxylate, a sulfonate, or any combinationthereof.

62. The method according to any of clauses 52-61, wherein the fiberfurther comprises an additional polymer.

63. The method according to clause 62, wherein the additional polymer isselected from the group consisting of a polyvinyl alcohol, a polyvinylacetate, a polyacrylate, a water-soluble acrylate copolymer, a polyvinylpyrrolidone, a polyethylenimine, a pullulan, a guar gum, a gum Acacia, axanthan gum, a carrageenan, a starch, a modified starch, a polyalkyleneoxide, a polyacrylamide, a polyacrylic acid, a cellulose, a celluloseether, a cellulose ester, a cellulose amide, a polycarboxylic acid, apolyaminoacid, a polyamide, a gelatin, dextrin, copolymers of theforegoing, and any combination of any of the foregoing additionalpolymers or copolymers.

64. The method according to any of clauses 52-63, wherein themodification agent comprises an anhydride, a carboxylic acid, analcohol, an ester, an ether, a sulfonic acid, a sulfonate, a clickchemistry reagent, an amide, an amine, a lactam, a nitrile, a ketone, anallyl containing compound, an acetyl containing compound, a halogen, analkyl containing compound, an imide, an acetal containing compound, anenolate, a nitro containing compound, a silane, or any combinationthereof.

65. The method according to any of clauses 52-64, wherein themodification agent comprises an anhydride.

66. The method according to clause 65, wherein the anhydride comprisesacetic anhydride, propionic anhydride, isobutyric anhydride, maleicanhydride, phthalic anhydride, glutaric anhydride, itaconic anhydride,citraconic anhydride, glutaconic anhydride, or any combination thereof.

67. The method according to clause 53, wherein the modification agent isprovided in an amount of about 0.2% to about 75% (w/w) based on theweight of the solvent.

68. The method according to clause 53, wherein the plurality of fibersare not soluble in the solvent for a duration of contact of the fiberwith the solvent.

69. The method according to clause 2, wherein the fiber comprises acopolymer of vinyl alcohol and vinyl acetate having a degree ofhydrolysis of about 88%, about 92%, or about 96%, the modification agentcomprises maleic anhydride, the solvent comprises methanol, and themethod further comprises admixing an activator comprising sodiumhydroxide with the fiber, the modification agent, and the solvent.

70. The method according to clause 2, wherein the fiber comprises acopolymer of vinyl alcohol and vinyl acetate having a degree ofhydrolysis of about 88%, about 92%, or about 96%, the modification agentcomprises maleic anhydride, and the solvent comprises methanol, andcontacting a surface of a fiber comprising a polymer with a modificationagent comprises:

combining the fiber and the solvent to form a mixture;

heating the mixture to about 55° C. to about 75° C. to form a heatedmixture;

adding to the heated mixture the maleic anhydride and an activatorcomprising sodium hydroxide to form a reaction mixture; and

stirring the reaction mixture at about 55° C. to about 75° C., for about3 to 7 hours.

71. The method according to clause 53, wherein the plurality of fiberscomprise a copolymer of vinyl alcohol and vinyl acetate having a degreeof hydrolysis of about 88%, about 92%, or about 96%, the modificationagent comprises maleic anhydride, the solvent comprises methanol, andthe method further comprises admixing an activator comprising sodiumhydroxide with the fiber, the modification agent, and the solvent.

72. The method according to clause 53, wherein the plurality of fiberscomprise a copolymer of vinyl alcohol and vinyl acetate having a degreeof hydrolysis of about 88%, about 92%, or about 96%, the modificationagent comprises maleic anhydride, and the solvent comprises methanol,and contacting a surface of a fiber comprising a polymer with amodification agent comprises:

combining the fiber and the solvent to form a mixture;

heating the mixture to about 55° C. to about 75° C. to form a heatedmixture;

adding to the heated mixture the maleic anhydride and an activatorcomprising sodium hydroxide to form a reaction mixture; and

stirring the reaction mixture at about 55° C. to about 75° C., for about3 to 7 hours.

EXAMPLES Fibers as Starting Materials

As shown in Table 2, five fibers, Fiber A, Fiber B, Fiber C, Fiber D,and Fiber E, which comprise a copolymer of vinyl acetate and vinylalcohol having a degree of hydrolysis of 88%, 92%, 96%, 98%, and 99.99%,respectively, are examples of the starting materials. These fibers haveuniform composition, and have additional properties shown in Table 2.Fibers A-C, particularly Fiber A, were used as the starting materials inthe Examples described herein. The descriptions are also applicable toFibers D and E. In the Examples and Comparative Examples describedherein, Fiber A used has a fineness of 2.2 dtex.

TABLE 2 Viscosity Solubility Elonga- (4% DH Fineness Temp Tenacity tionFiber solution) (mol %) (dtex) (° C.) (cN/dtex) (%) A 22-23 88 1.7 20 520 2.2 B 22-23 92 1.7 30 6 18 2.2 C 22-23 96 1.2 40 7 15 1.7 D 22-23 981.2 70 7 12 1.7 E 22-23 99.99 1.2 95 9 10 1.7

Examples 1-3

Fibers A, B, and C comprising vinyl alcohol moieties and having a degreeof hydrolysis of 88%, 92% or 96% as the sole fiber forming material orin combination with other fiber forming materials were post-processmodified as follows. In the Examples, a polymer comprising vinyl alcoholmoieties is referred as “a polyvinyl alcohol polymer,” and a fibercomprising such a polymer is referred as “a polyvinyl alcohol (PVOH)fiber.” 4 g of the polyvinyl alcohol fibers were immersed in 200 g ofmethanol. The mixture of polyvinyl alcohol fibers and methanol washeated to 70° C. The fibers do not dissolve in the methanol. 5 g maleicanhydride and 60 mL of 1 M sodium hydroxide in water were added into theheated mixture. The resulting mixture is agitated at 70° C. for 5 hours.The resulting modified fibers were filtered and washed with methanol.The modified fibers were dried in a fume hood for 12 hours. Theresulting dried fibers were measured using the titration methoddisclosed herein, MSTM 205, FTIR-ATR, and/or DSC, and the chemicalmodification was confirmed.

Thus, Examples 1-3 show using methods of the disclosure to preparepost-process carboxylate-modified polyvinyl alcohol fibers. Amodification reaction of a copolymer of vinyl acetate and vinyl alcoholwith maleic anhydride is illustrated in Scheme (1) as follows:

The esterification reaction between a hydroxyl group in the copolymerand maleic anhydride provides a modified polymer having monomethylmaleate (MMM) or salt thereof chemically attached on the polymerbackbone through an ester bond. The modified fibers have a core-sheathstructure as described herein.

Additional solvents such as THF and DCM (dichoromethane) and additionalanhydrides such as glutaric anhydride, itaconic anhydride, and phthalicanhydrides were used. The modification reactions were performed atdifferent temperatures for different periods of time. The fibers stayedintact in each solvent. Methanol solubilizes reactants such asanhydrides and bases (e.g., NaOH, KOH), while THF and DCM partiallysolubilizes the bases. THF and DCM are more preferred than methanolbecause THF and DCM favor esterification over saponification of thepolymer. When methanol is used, saponification may occur and theesterification reaction occurs at higher temperatures. When THF or DCMwas used as a solvent, a modified polymer having monomethyl maleate(MMM) or salt thereof can be obtained through the esterificationreaction between a hydroxyl group in the copolymer and maleic anhydride,without saponification. Such a modification was confirmed by FT-IRresults, for example, the appearance of a peak at 1580 cm⁻¹ from thecarboxylate group at the end of MMM. Meanwhile, the solubility of thenonwoven web comprising such modified fibers was maintained. Themodification reactions for Fiber A with anhydrides including maleicanhydride, glutaric anhydride, itaconic anhydride, and phthalicanhydride were performed and compared under the same conditions, forexample, in THF at 60° C. for 5 hours. When glutaric anhydride anditaconic anhydride were used, the modified fibers showed FT-IR resultssimilar to that of MMM, while the fibers modified with itaconicanhydride showed lower signal intensity of modification. Themodification with phthalic anhydride showed a very strong intensity, thehighest intensity among the modifications with the four anhydrides undera same condition, due to conjugated carbon bonds near the binding site,and also showed a benzene ring signal near 1450 cm⁻¹. Phthalic anhydridewas selected additionally because of its antimicrobial properties.Modification of the fibers with each anhydride was also achieved at roomtemperature. The modified fibers with maleic anhydride, phthalicanhydride, and glutaric anhydride maintained the desired whiteappearance of unmodified fibers. Experimental results also showed thatglass transition temperatures of the same polymers had no significantdifference before and after the chemical modification.

In the Examples described herein, the starting fibers include acopolymer of vinyl acetate and vinyl alcohol, and the modified fiberswere chemically modified with functional groups such as carboxylate andsulfonate. The descriptions are also applicable to the fibers comprisinga modified copolymer, such as an anionically modified PVOH copolymer,having carboxylate and/or sulfonate, and such fibers are furtherchemically modified with a modification agent to increase the degree ofmodification.

Examples 4-6

Fibers A-C comprising vinyl alcohol moieties and having a degree ofhydrolysis of 88%, 92% or 96% as the sole fiber forming material or incombination with other fiber forming materials were post-processmodified as follows. 5 g of the polyvinyl alcohol fibers were immersedin methanol. The fibers do not dissolve in the solvent. The resultingmixture was heated to about 30° C. to about 80° C. Aminopropyl sulfonateand an activator (e.g., an acid or a base) were then added to the heatedmixture. The heated mixture was then agitated for 1 hour to 10 hours.After agitation, the mixture was cooled and the fibers were separatedfrom the solvent. The resulting modified fibers were dried to remove anyresidual solvent prior to measuring the degree of modification of thepolymer in the fibers using the titration method disclosed herein, MSTM205, FTIR-ATR, and/or DSC.

Thus, Examples 4-6 show using methods of the disclosure to preparepost-process sulfonate-modified polyvinyl alcohol fibers.

Examples 7-9

Fibers A-C comprising vinyl alcohol moieties and having a degree ofhydrolysis of 88%, 92% or 96% as the sole fiber forming material or incombination with other fiber forming materials were post-processmodified as follows. 5 g of the polyvinyl alcohol fibers were immersedin methanol. The fibers do not dissolve in the solvent. The resultingmixture was heated to about 30° C. to about 80° C. A lactam comprising apyrrolidone or a caprolactam, and an activator (e.g., an acid or a base)were then added to the heated mixture. The heated mixture was thenagitated for 1 hour to 10 hours. After agitation, the mixture was cooledand the fibers were separated from the solvent. The resulting modifiedfibers were dried to remove any residual solvent prior to measuring thedegree of modification of the polymer using the titration methoddisclosed herein, MSTM 205, FTIR-ATR, and/or DSC.

Thus, Examples 7-9 show using methods of the disclosure to preparepost-process polyvinyl alcohol fibers chemically modified with a lactam,through a ring-opening reaction of the lactam with a hydroxyl group fromthe vinyl alcohol moieties.

Examples 10-12

Fibers A-C comprising vinyl alcohol moieties and having a degree ofhydrolysis of 88%, 92% or 96% as the sole fiber forming material or incombination with other fiber forming materials were post-processmodified as follows. 5 g of the polyvinyl alcohol fibers were immersedin methanol. The fibers do not dissolve in the solvent. The resultingmixture was heated to about 30° C. to about 80° C. A sulfonic acidcomprising 2-acrylamido-2-methylpropanesulfonic acid, and an activator(e.g., an acid or a base) were then added to the heated mixture. Theheated mixture was then agitated for 1 hour to 10 hours. Afteragitation, the mixture was cooled and the fibers were separated from thesolvent. The resulting modified fibers were dried to remove any residualsolvent prior to measuring the degree of modification of the polymerusing the titration method disclosed herein, MSTM 205, FTIR-ATR, and/orDSC.

Thus, Examples 10-12 show using methods of the disclosure to preparepost-process sulfonic acid-modified polyvinyl alcohol fibers.

Examples 13-15

Fibers (Fiber A) comprising a copolymer of vinyl acetate and vinylalcohol and having an 88% degree of hydrolysis were chemically modifiedwith an anhydride in THF at 60° C. for 5 hours. The fibers were bondedusing a hot through-air bonding method to provide nonwoven samples.FIGS. 6-8 show the ATR-FTIR curves of nonwoven samples (Examples 13-15)comprising fibers chemically modified with glutaric anhydride, maleicanhydride, and phthalic anhydride, respectively. The amount of anhydrideadded was calculated based on the degree of hydrolysis of the fibers(i.e., 88% for Fiber A) for the content of hydroxyl groups, and thedegree of modification needed. For example, to achieve 25% chemicalmodification (i.e., conversion of 25% of hydroxyl groups), an amount ofmaleic anhydride, glutaric anhydride, or phthalic anhydride needed was1.343 g, 1.564 g, or 2.03 g, respectively. The degree of polymerizationof Fiber A was 1700. The curve of the nonwoven sample comprising fiberswithout modification (Comparative Example 1) is shown in a dotted linein each of FIGS. 6-8. The peaks in the FT-IR curves can be used tocharacterize the chemical modification and the degree of modification.For example, as shown in FIG. 7, the peak(s) in the range of 1734-1713cm⁻¹ indicate a carbonyl group (C═O, stretch) such as that in theacetate group. The appearance of a peak at 1580 cm⁻¹ is from theunbonded carboxylate group at the end of MMM. The peaks of 1427 cm⁻¹ and1374 cm⁻¹ correspond to a methylene group in the polymer backbone (i.e.,CH₂ bending) and methyl in acetate side groups, respectively.

As shown in FIGS. 6-8, unbonded carboxyl groups at the end of anhydridemoiety after the ring-opening reaction can be seen based on the peakbetween 1600 cm⁻¹ and 1520 cm⁻¹. This illustrates that the carboxylategroups are not crosslinked in the resulting modified polymers.

For the nonwoven samples made for solubility and mechanical testing, thefibers included 98.25% of Fiber A and 1.75% of polyethylene(PE)/polyethylene terephthalate (PET). The fibers are disposed betweenstainless steel meshes. The bonding temperature of the through-airprocess was selected from 120° C., 160° C., or 180° C.

Example 16

Fibers (Fiber E) having PVOH copolymer with 99.99% degree of hydrolysiswere chemically modified with maleic anhydride in THF at 60° C. for 5hours to provide Example 16. Fiber E without treatment is ComparativeExample 2, which is not readily water-soluble. FIG. 9 shows ATR-FTIRresults of Example 16 and Comparative Example 2. A new peak around 1580cm⁻¹ appeared after the chemical modification. The FT-IR results furtherconfirmed that the chemical modification reaction occurs at the hydroxylgroups of vinyl alcohol moieties (i.e., the backbone of the PVOHcopolymer), not at the vinyl acetate moieties. The modified fibers arewater-soluble.

Examples 17-20

FIG. 10 shows rupture time of through-air bonded nonwoven webs havingfibers (Fiber A) without and with chemical modification with ananhydride, such as maleic anhydride, glutaric anhydride, or phthalicanhydride, in THF at 60° C. for 5 hours. In FIG. 10, ComparativeExamples 3 and 4 (“CEx. 3” and “CEx. 4” as labelled in FIG. 10) arethrough-air bonded nonwoven webs having fibers (Fiber A) withoutchemical modification, while the fibers were immersed in THF at 60° C.for 5 hours, and then dried before the bonding process. The bondingtemperature of Comparative Examples 3 and 4 was 160° C. and 180° C.,respectively. Comparative Examples 3 and 4 are called positive controls.In Example 17 (“Ex. 17”), Example 18 (Ex. 18″), and Example 19 (“Ex.19”), the fibers were chemically modified with maleic anhydride,glutaric anhydride, and phthalic anhydride, respectively. The bondingtemperature was 160° C. for Examples 17, and 180° C. for Examples 18 and19. In these through-air bonded nonwoven samples including thecomparative examples described herein, the fibers initially included98.25% Fiber A and 1.75% of PE/PET.

FIG. 11 shows rupture time of nonwoven webs having fibers (Fiber A)without and with chemical modification with maleic anhydride in DCM atroom temperature for 5 hours. The nonwoven webs were made usingcalendaring bonding (30 gsm). Comparative Example 5 (“CEx. 5”) andComparative Example 6 (“CEx. 6”) as labelled in FIG. 11 are nonwovenwebs having fibers (Fiber A) without chemical modification, except thatComparative Example 6 was treated in DCM at room temperature for 5hours. Example 20 (“Ex. 20”) was chemically treated with maleicanhydride in DCM at room temperature for 5 hours. In the calendaringbonded samples including the comparative examples described herein, theinitial fibers included 100% of Fiber A without any other fibers such asPE/PET.

As shown in FIGS. 10-11, with chemical modification, solubility of thenonwoven samples is maintained. This also indicates that a cross-linkingreaction does not occur. Otherwise, the solubility will be hindered toshow a different solubility profile.

FIG. 12 shows tensile strength of through-air nonwoven webs havingfibers (Fiber A) without and with chemical modification with ananhydride, such as maleic anhydride, glutaric anhydride, or phthalicanhydride, in THF at 60° C. for 5 hours. The samples include Examples17-19 and Comparative Examples 3-4 as positive controls as describedabove. Two additional Comparative Examples (CEx. 3′ and CEx. 4′) werealso tested. CEx. 3′ and CEx. 4′ correspond to CEx. 3 and CEx. 4,respectively, except that the fibers were not immersed in THF at 60° C.for 5 hours, and were directly through-air bonded at 160° C. and 180°C., respectively.

FIG. 13 shows tensile strength of nonwoven webs having fibers (Fiber A)without and with chemical modification with maleic anhydride in DCM atroom temperature for 5 hours, including Example 20 and ComparativeExamples 5-6 as described above.

As shown in FIG. 12, the through-air samples having modified fibers havetensile strength slightly higher than those of Comparative Exampleswithout modification. As shown in

FIG. 13, the increase in tensile strength resulting from chemicalmodification is more significant for the nonwoven samples made bycalendar bonding.

FIG. 14 shows a glycerin holding capacity of through-air bonded nonwovenwebs having fibers (Fiber A) without and with chemical modification withan anhydride, such as maleic anhydride, glutaric anhydride, or phthalicanhydride, in THF at 60° C. for 5 hours. The initial loading of glycerinwas 50%. The initial loading is an amount of glycerin applied to asample based on the sample weight. For example, at 50% of loading, 0.5 gof glycerin was applied to 1 g of nonwoven sample. The glycerin holdingcapacity was measured as a percentage of retention of glycerin based onthe weight percentage of glycerin retained in a nonwoven sample after asoaking time of one hour under ambient conditions. The retention ofglycerin is an indicator of retention of polar additives used innonwoven products. Additionally, glycerin is a preferred carrier inpersonal hygiene products. In FIG. 14, the samples include Examples 17,18, and 19; and Comparative Examples 3-4 as described above. Inaddition, Comparative Example 7 (“CEx. 7”) is a through-air bondednonwoven web having fibers (Fiber A) without chemical modification andbonded at 120° C. The samples with chemical modification showed at least10% increase in retention of glycerin. For example, compared toComparative Example 3, Example 17 with maleic anhydride showed asignificant increase in retention of glycerin.

FIG. 15 shows a glycerin holding capacity of nonwoven webs having fibers(Fiber A) without and with chemical modification with maleic anhydridein DCM at room temperature for 5 hours, including Example 20 andComparative Examples 5-6 made through calendar bonding as describedabove. The initial loading of glycerin was 50%. As shown in FIG. 15,Example 20 with maleic anhydride modification showed a significantincrease (by at least 20%) in retention of glycerin at this low (50%)loading.

FIGS. 16 and 17 are similar to FIGS. 14 and 15, respectively, exceptthat the initial loading of glycerin (180%) was much higher. As shown inFIGS. 16 and 17, maleic anhydride modification provides a significantincrease (by at least 20%) in retention of glycerin at this high (180%)loading.

Some results of Examples 17-20 are also summarized in Tables 3 and 4.

TABLE 3 Glycerin Holding Glycerin Holding Solubility Tensile CapacityCapacity (23° C.) Strength (% retention at (% retention at Rupture TimeMax Load Sample 50% Loading) 180% loading) (s) (N) Modified Through-air41.61% 34.21% 6.33 26.62 Bonded Nonwoven Stdev: 5% Stdev: 4.99% Stdev:0.94 Stdev: 8.23 (Maleic Anhydride, Ex. 17) Modified Through-air 35.88%17.61% 6.67 16.94 N Bonded Nonwoven Stdev: 1.77% Stdev: 6.46% Stdev:0.47 Stdev: 4.83 (Glutaric Anhydride, Ex. 18) Modified Through-air48.22% 22.22% 7.33 19.70 Bonded Nonwoven Stdev: 19.3% Stdev: 2.66%Stdev: 0.47 sec Stdev: 8.58 (Phthalic Anhydride, Ex. 19) Non-modified39.65% 15.59% 29     8.37 Through-air Bonded Stdev: 7.91% Stdev: 5.10%Stdev: 12.19 Stdev: 0.38 Nonwoven (CEx′ 4) +control Non- 38.65% 27.47%10.33  29.52 modified Through-air Stdev: 7.46% Stdev: 4.59% Stdev: 0.47Stdev: 5.69 Nonwoven (CEx 4)

TABLE 4 Glycerin Holding Glycerin Holding Solubility Tensile CapacityCapacity (23° C.) Strength, (% retention at (% retention at Rupture TimeMax Load Sample 50% Loading) 180% Loading) (s) (N) Modified Nonwoven67.96% 40.04% 8 9.20 (Maleic Anhydride, Stdev: 3.80% Stdev: 3.17% Stdev:0.82 Stdev: Ex. 20) Non-modified 49.23% 22.11%   8.67 4.21 NonwovenStdev: 13.33% Stdev: 4.80% Stdev: 0.47 Stdev: 2.05 (CEx 5) +controlNonwoven 53.74% 33.77% 8 6.13 (CEx 6) Stdev: 7.00% Stdev: 5.58% Stdev:0.00 Stdev: 1.82

Example 21

FIG. 18 shows ATR-FTIR results of an interior region (“inside region”)and a surface region (“outside region”) of an exemplary block comprisinga copolymer of vinyl acetate and vinyl alcohol without and with chemicalmodification with maleic anhydride in in THF at 60° C. for 5 hours. Theblock sample was made of a copolymer of vinyl acetate and vinyl alcoholhaving a degree of hydrolysis of 88%. Each block sample had a size of1.5 centimeters (cm)×1. 5 cm×0.5 cm. The sample was modified with maleicanhydride in in THF at 60° C. for 5 hours. After modification anddrying, the sample having a thickness in a range of from 0.1 mm to 0.5mm was cut from the block sample and then tested using ATR-FTI R. Themodified sample is Example 21, and the FT-IR curve of the initial blockwithout modification is shown in a dotted line in FIG. 18. Based on theFTIR results, pendent groups resulting from esterification of maleicanhydride are mainly limited to the surface region of the block,therefore, creating a relatively higher degree of modification in theouter region and a relatively lower degree of modification in the innerregion of the sample. This confirmed that the fibers modified under thesame conditions have a core-sheath structure as described herein.

The foregoing description is given for clearness of understanding only,and no unnecessary limitations should be understood therefrom, asmodifications within the scope of the disclosure may be apparent tothose having ordinary skill in the art.

All patents, publications and references cited herein are hereby fullyincorporated by reference. In case of conflict between the presentdisclosure and incorporated patents, publications and references, thepresent disclosure should control.

What is claimed is:
 1. A method of treating a fiber, comprising:contacting a surface of a fiber comprising a polymer comprising at leastone of a vinyl acetate moiety or a vinyl alcohol moiety with amodification agent to chemically modify at least a portion of thepolymer with the modification agent in a region of the fiber comprisingat least the surface of the fiber so as to form a modified fiber.
 2. Themethod according to claim 1, further comprising adding a solvent for themodification agent.
 3. The method according to claim 2, whereincontacting a surface of the fiber with the modification agent comprisesadmixing the fiber comprising at least one of a vinyl acetate moiety ora vinyl alcohol moiety, the modification agent, and the solvent.
 4. Themethod according to claim 2, wherein the fiber is not soluble in thesolvent for a duration of contact of the fiber with the solvent.
 5. Themethod according to claim 2, further comprising heating the fiber in thesolvent prior to contacting a surface of the fiber with the modificationagent.
 6. The method according to claim 2, further comprising heatingthe fiber, the modification agent, and the solvent.
 7. The methodaccording to claim 1, wherein the surface of the fiber is contacted withthe modification agent for a period of time up to about 48 hours.
 8. Themethod according to claim 1, wherein the surface of the fiber iscontacted with the modification agent at a temperature in a range offrom about 10° C. to about 100° C.
 9. The method according to claim 1,wherein the polymer comprising at least one of a vinyl acetate moiety ora vinyl alcohol moiety has a degree of hydrolysis greater than about 79%and less than about 99.9% prior to contacting a surface of the fiberwith the modification agent.
 10. The method according to claim 1,wherein contacting a surface of the fiber with the modification agent isperformed under conditions sufficient to provide a controlled amount ofchemical modification to the polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety and/or controlled increase ofchemical modification to the polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety.
 11. The method according toclaim 1, wherein the chemical modification of at least a portion of thepolymer with the modification agent comprises one or more of thefollowing: esterification, amidation, amination, carboxylation,nitration, acyloin condensation, allylation, acetylation, imidization,halogenation, sulfonation, alkylation, enolization, nitrosation, andsilane coupling.
 12. The method according to claim 1, further comprisingadmixing an activator with the fiber and the modification agent, theactivator comprising an acid, a base, an aziridine, a free radicalinitiator, or a combination thereof.
 13. The method according to claim1, wherein the modification agent comprises an anhydride, a carboxylicacid, an alcohol, an ester, an ether, a sulfonic acid, a sulfonate, aclick chemistry reagent, an amide, an amine, a lactam, a nitrile, aketone, an allyl containing compound, an acetyl containing compound, ahalogen, an alkyl containing compound, an imide, an acetal containingcompound, an enolate, a nitro containing compound, a silane, anaziridine, an isocyanate, or any combination thereof.
 14. The methodaccording to claim 1, wherein the modified fiber comprises amonocarboxylic acid, a dicarboxylic acid, a sulfonic acid, a sulfonate,a click chemistry reagent, an amide, an amine, a nitrile, a ketone, anester, an allyl, an acetyl, a halogen, an alkyl, an imide, an acetal, anenolate, a nitro, a silane, or any combination thereof.
 15. The methodaccording to claim 13, wherein the sulfonate comprises aminopropylsulfonate.
 16. The method according to claim 13, wherein the lactamcomprises a pyrrolidone or a caprolactam.
 17. The method according toclaim 13, wherein the sulfonic acid comprise2-acrylamido-2-methylpropanesulfonic acid.
 18. The method according toclaim 13, wherein the monocarboxylic acid or the dicarboxylic acidcomprises acetic acid, maleic acid, monoalkyl maleate, dialkyl maleate,fumaric acid, monoalkyl fumarate, dialkyl fumarate, itaconic acid,monoalkyl itaconate, dialkyl itaconate, citraconic acid, monoalkylcitraconate, dialkyl citraconate, mesaconic acid, monoalkyl mesaconate,dialkyl mesaconate, glutaconic acid, monoalkyl glutaconate, dialkylglutaconate, alkyl (alkyl)acrylates, alkali metal salts of theforegoing, hydrolyzed alkali metal salts thereof, esters thereof, or anycombination thereof.
 19. The method according to claim 1, wherein themodification agent comprises an anhydride.
 20. The method according toclaim 19, wherein the anhydride is an organic acid anhydride and theorganic acid anhydride comprises acetic anhydride, propionic anhydride,isobutyric anhydride, maleic anhydride, phthalic anhydride, glutaricanhydride, itaconic anhydride, citraconic anhydride, glutaconicanhydride, or any combination thereof.
 21. The method according to claim19, wherein the anhydride comprises maleic anhydride.
 22. The methodaccording to claim 2, wherein the modification agent is provided in anamount of about 0.2% to about 75% (w/w) based on the weight of thesolvent.
 23. The method according to claim 2, wherein the solventcomprises a polar solvent.
 24. The method according to claim 2, whereinthe solvent comprises one or more solvents selected from the groupconsisting of methanol, ethanol, n-propanol, isopropanol,tetrahydrofuran, dichloromethane, acetone, N-methylpyrrolidone,acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, formic acid,water, and any combination thereof.
 25. The method according to claim 2,wherein the solvent comprises a nonpolar solvent.
 26. The methodaccording to claim 2, wherein the solvent comprises an alcohol that is aliquid under admixing conditions.
 27. The method according to claim 2,wherein the solvent comprises a mixture of a first solvent and a secondsolvent.
 28. The method according to claim 27, wherein the first solventcomprises water and the second solvent comprises an alcohol.
 29. Themethod according to claim 28, wherein the second solvent comprisesmethanol, ethanol, n-propanol, isopropanol, or any combination thereof.30. The method according to claim 1, wherein contacting a surface of thefiber with the modification agent is performed under conditionssufficient to provide an anionically modified polymer.
 31. The methodaccording to claim 30, wherein the anionically modified polymercomprises a carboxylate, a sulfonate, or a combination thereof.
 32. Themethod according to claim 1, wherein the polymer comprising at least oneof a vinyl acetate moiety or a vinyl alcohol moiety comprises apolyvinyl alcohol homopolymer, a polyvinyl acetate homopolymer, apolyvinyl alcohol copolymer, or combinations thereof.
 33. The methodaccording to claim 32, wherein the polyvinyl alcohol copolymer is acopolymer of vinyl acetate and vinyl alcohol.
 34. The method accordingto claim 1, wherein the fiber further comprises an additional polymer.35. The method according to claim 34, wherein the additional polymer isselected from the group consisting of a polyvinyl alcohol, a polyvinylacetate, a polyacrylate, a water-soluble acrylate copolymer, a polyvinylpyrrolidone, a polyethylenimine, a pullulan, a guar gum, a gum Acacia, axanthan gum, a carrageenan, a starch, a modified starch, a polyalkyleneoxide, a polyacrylamide, a polyacrylic acid, a cellulose, a celluloseether, a cellulose ester, a cellulose amide, a polycarboxylic acid, apolyamino acid, a polyamide, a gelatin, a dextrin, copolymers of theforegoing, and any combination of any of the foregoing additionalpolymers or copolymers.
 36. The method according to claim 1, whereincontacting a surface of the fiber with the modification agent isperformed under conditions sufficient to provide a fiber having atransverse cross-section having a core-sheath structure including a coreand a sheath, wherein the polymer of the core has a first amount ofchemical modification and the polymer of the sheath has a second amountof chemical modification greater than the first amount.
 37. The methodaccording to claim 1, wherein contacting a surface of the fiber with themodification agent is performed under conditions sufficient to provide afiber having a transverse cross-section characterized by an increasinggradient in the amount of chemical modification of the polymer from aninterior region to the surface region.
 38. The method according to claim1, wherein contacting a surface of the fiber with the modification agentis performed under conditions sufficient to provide a fiber having atransverse cross-section characterized by the polymer having an equalamount of chemical modification across the transverse cross-section. 39.The method according to claim 1, wherein the fiber is water-soluble ornot water soluble prior to contacting a surface of the fiber with themodification agent.
 40. The method according to claim 1, wherein themodified fiber is water-soluble.
 41. The method according to claim 1,wherein, prior to contacting a surface of the fiber with themodification agent, the fiber has a first complete dissolutiontemperature and the modified fiber has a second complete dissolutiontemperature different from the first complete dissolution temperature.42. The method according to claim 41, wherein the first completedissolution temperature is greater than the second complete dissolutiontemperature.
 43. The method according to claim 41, wherein the firstcomplete dissolution temperature is lower than the second completedissolution temperature.
 44. The method according to claim 1, whereincontacting a surface of the fiber with the modification agent isperformed by one or more of the following: immersion, spraying, transfercoating, wicking, foaming, brushing, rolling, humidification, vapordeposition, printing, or any combination thereof.
 45. The methodaccording to claim 44, wherein contacting a surface of the fiber withthe modification agent and a solvent is performed after formation of thefiber as part of a continuous inline process.
 46. The method accordingto claim 1, wherein the fiber is in motion during the contacting of asurface of the fiber with the modification agent and a solvent.
 47. Themethod according to claim 1, wherein contacting a surface of the fiberwith the modification agent is performed in a batchwise process.
 48. Themethod according to claim 1, wherein the fiber comprises staple fiber,staple yarn, fiber fill, needle punch fabrics, bonding fibers, or anycombination thereof.
 49. The method according to claim 1, furthercomprising washing and drying the fiber after contacting a surface ofthe fiber with the modification agent.
 50. The method according to claim49, wherein washing the fiber comprises rinsing the fiber with anon-solvent.
 51. The method according to claim 49, wherein drying thefiber comprises one or more of the following: air jet drying, agitating,vortexing, centrifuging, or any combination thereof.
 52. A method oftreating a nonwoven web comprising a plurality of fibers, each fiber ofthe plurality of fibers comprising a polymer comprising at least one ofa vinyl acetate moiety or a vinyl alcohol moiety, the method comprising:contacting at least a portion of the nonwoven web with a modificationagent to chemically modify the polymer in a first region of each fiberwith the modification agent so as to provide a modified nonwoven web.53. The method according to claim 52, further comprising adding asolvent for the modification agent.
 54. The method according to claim52, wherein contacting at least a portion of the nonwoven web with themodification agent is performed by one or more of the following:immersion, spraying, transfer coating, wicking, foaming, brushing,rolling, humidification, vapor deposition, printing, or any combinationthereof.
 55. The method according to claim 52, further comprisingconcurrently bonding the plurality of fibers into the nonwoven web whilecontacting the at least a portion of the nonwoven web with themodification agent.
 56. The method according to claim 55, whereinbonding the plurality of fibers comprises chemical bonding the pluralityof fibers.
 57. The method according to claim 55, wherein bonding theplurality of fibers comprises using a heat activated catalysis.
 58. Themethod according to claim 52, wherein the polymer comprising at leastone of a vinyl acetate moiety or a vinyl alcohol moiety comprises apolyvinyl alcohol homopolymer, a polyvinyl acetate homopolymer, apolyvinyl alcohol copolymer, or any combination thereof.
 59. The methodaccording to claim 58, wherein the polyvinyl alcohol copolymer is acopolymer of vinyl acetate and vinyl alcohol.
 60. The method accordingto claim 58, wherein the polyvinyl alcohol copolymer comprises ananionically modified copolymer.
 61. The method according to claim 58,wherein the anionically modified copolymer comprises a carboxylate, asulfonate, or any combination thereof.
 62. The method according to 52,wherein the fiber further comprises an additional polymer.
 63. Themethod according to claim 62, wherein the additional polymer is selectedfrom the group consisting of a polyvinyl alcohol, a polyvinyl acetate, apolyacrylate, a water-soluble acrylate copolymer, a polyvinylpyrrolidone, a polyethylenimine, a pullulan, a guar gum, a gum Acacia, axanthan gum, a carrageenan, a starch, a modified starch, a polyalkyleneoxide, a polyacrylamide, a polyacrylic acid, a cellulose, a celluloseether, a cellulose ester, a cellulose amide, a polycarboxylic acid, apolyamino acid, a polyamide, a gelatin, dextrin, copolymers of theforegoing, and any combination of any of the foregoing additionalpolymers or copolymers.
 64. The method according to 52, wherein themodification agent comprises an anhydride, a carboxylic acid, analcohol, an ester, an ether, a sulfonic acid, a sulfonate, a clickchemistry reagent, an amide, an amine, a lactam, a nitrile, a ketone, anallyl containing compound, an acetyl containing compound, a halogen, analkyl containing compound, an imide, an acetal containing compound, anenolate, a nitro containing compound, a silane, or any combinationthereof.
 65. The method according to claim 52, wherein the modificationagent comprises an anhydride.
 66. The method according to claim 65,wherein the anhydride comprises acetic anhydride, propionic anhydride,isobutyric anhydride, maleic anhydride, phthalic anhydride, glutaricanhydride, itaconic anhydride, citraconic anhydride, glutaconicanhydride, or any combination thereof.
 67. The method according to claim53, wherein the modification agent is provided in an amount of about0.2% to about 75% (w/w) based on the weight of the solvent.
 68. Themethod according to claim 53, wherein the plurality of fibers are notsoluble in the solvent for a duration of contact of the fiber with thesolvent.
 69. The method according to claim 2, wherein the fibercomprises a copolymer of vinyl alcohol and vinyl acetate having a degreeof hydrolysis of about 88%, about 92%, or about 96%, the modificationagent comprises maleic anhydride, the solvent comprises methanol, andthe method further comprises admixing an activator comprising sodiumhydroxide with the fiber, the modification agent, and the solvent. 70.The method according to claim 2, wherein the fiber comprises a copolymerof vinyl alcohol and vinyl acetate having a degree of hydrolysis ofabout 88%, about 92%, or about 96%, the modification agent comprisesmaleic anhydride, and the solvent comprises methanol, and contacting asurface of a fiber comprising a polymer with a modification agentcomprises: combining the fiber and the solvent to form a mixture;heating the mixture to about 55° C. to about 75° C. to form a heatedmixture; adding to the heated mixture the maleic anhydride and anactivator comprising sodium hydroxide to form a reaction mixture; andstirring the reaction mixture at about 55° C. to about 75° C., for about3 to 7 hours.
 71. The method according to claim 53, wherein theplurality of fibers comprise a copolymer of vinyl alcohol and vinylacetate having a degree of hydrolysis of about 88%, about 92%, or about96%, the modification agent comprises maleic anhydride, the solventcomprises methanol, and the method further comprises admixing anactivator comprising sodium hydroxide with the fiber, the modificationagent, and the solvent.
 72. The method according to claim 53, whereinthe plurality of fibers comprise a copolymer of vinyl alcohol and vinylacetate having a degree of hydrolysis of about 88%, about 92%, or about96%, the modification agent comprises maleic anhydride, and the solventcomprises methanol, and contacting a surface of a fiber comprising apolymer with a modification agent comprises: combining the fiber and thesolvent to form a mixture; heating the mixture to about 55° C. to about75° C. to form a heated mixture; adding to the heated mixture the maleicanhydride and an activator comprising sodium hydroxide to form areaction mixture; and stirring the reaction mixture at about 55° C. toabout 75° C., for about 3 to 7 hours.